That's what backhand solution means. If they just let the French attack them (presumably ignoring the British here, as the UK *will* not let the Germans make Europe their bitch) then they're pretty much doomed to lose the war faster than IOTL.
That is a bit of a myth. Even in OTL with not the best relations between Germany and the UK, the majority of the cabinet and a significant portion of MPs were against an entry into the war without an acceptable casus belli. Actually there was only one member of the cabinet who supported intervention under any circumstances, and that was Churchill. Asquith and Grey both leaned towards intervention, but saw the difficulties in selling this to the public and the parliament, the latter being a very important factor since the UK was a democracy and without parliamentary consent an entry into the war was impossible. Crewe maybe could be counted towards the pro-intervention faction, too, but his stance on the subject is much more spiffy.
Although Bonar Law, the leader f the Unionists, supported immediate intervention and in the end Asquith, Grey and Churchill (and maybe Crewe) did that, too, they did it not all with the same fervor. Asquith's priority was the unity of his government, of the cabinet and the party. Grey had already mentioned that he might be willing under certain circumstances to let Britain stay aside. That is if British interests were not touched. Grey thought that the British public would not have been willing to go to war for Russia and he always emphasised that if France get into the war because of Russia it was their own fault. If Germany had taken a neutral stance in the west, that is neither invading Belgium nor attacking over the French border, Grey might very well had lived with that. Grey threatened resignation only for the case that the cabinet would support neutrality in any circumstances, which the cabinet had not. Only Churchill was quiet adamant on intervention regardless of the situation.
If Asquith had really decided to go with the Conservatives I am not sure he would have had a majority in parliament. Most likely only Churchill and Grey would have followed him. Lloyd George than would have led the vast majority of the cabinet, including a large portion of the Liberal party which could have also relied on Labour's support (which would have even gone further). Lloyd George was a quiet influential figure in the Liberal party and would have been a formidable opponent. Either way such an entry would have been difficult to sell to the public, would have sparked lots of heated debates and a government of national unity would have been difficult to promote under these circumstances. Not to say what would have happened if those in the know had revealed Grey's secret dealings with the French up to and including to send a BEF to the continent.
Besides that according to Thirteenth Days by Clive Ponting, although the possibility of a coalition of Liberal Imperialists and Conservatives was known it had not become an issue in the discussion and thus might not have been considered seriously at all:
2nd August:
“The majority view around the cabinet table was expressed by Samuel: 'We were not entitled to carry England to the war for the sake of our goodwill for France, or for the sake of maintaining the strength of France and Russia against that of Germany and Austria. This opinion is shared by the majority of the cabinet with various degrees of emphasis on the several parts of it.'”
“Although the letter [by Bonar Law supporting immediate intervention] opened the possibility of a pro-war coalition being formed from the small minority in the cabinet who supported war alongside France in any circumstances and the opposition, in practice the letter had little impact on the discussion.”
As long as Germany would have taken a defensive stance in the west I doubt a British intervention. Russia was not looked favourably upon. Britain would have intervened in the end if France as a Great Power was really in danger. That might mean a late entry into the war, only a blockade going or just threatening Biritish involvement to ensure early peace talks favourably to France.
A defensive stance might also bring great difficulties for France. Although France was obliged to enter the war on Russia's side they did want Germany to be in the wrong. The decision makers found it paramount that Germany has to attack first. If Germany just was sitting in their forts and did nothing there is the question how long was France willing to wait for a German attack? And if its not coming forth, would they really risk to attack, although that might have turned public opinion against them? What if butterflies had Jaurès still living? And all the while the French would still have no positive decision by the British government that they would intervene on their side. That would really be a dilemma which would grow more seriously every day the French would wait while their Russian ally would have to take on Germany and A-H.
Here are some other quotations of Thirteen Days, by Clive Ponting, Chatto & Windus, London 2002:
31st July:
“Grey continually emphasised that Britain 'was bound by no treaties' and that if Berlin and Vienna showed flexibility and Russia put itself in the wrong, 'he could sponsor the idea of not immediately taking the part of France'.
[…]
Harcourt also wrote, clearly reflecting Grey's line, 'if Russ[ia] unreasonable we wash our hands'. Pease himself described the general view in his diary: 'British opinion would not now enable us to support France – a violation of Belgium might alter public opinion, but we could say nothing to commit ourselves.'
[…]
“In the light of the financial crisis, the cabinet felt 'British neutrality might be the only way of averting the complete collapse of European credit'.”
1st August:
Asquith, Grey and Haldane meet: “There seems to have been a general feeling, reflecting the mood of the cabinet on the previous day, that France was too closely tied to Russia and that it was Russia that was provoking a European war by mobilising. Britain had stood by France in the Moroccan disputes of 1906 and 1911 because Morocco formed part off the Anglo-French colonial agreements. Was this the case now? Did Britain have to support France just because its ally had intervened in the dispute between Austria-Hungary and Serbia – a dispute in which Britain had no direct interest? Grey had, at the previous day's cabinet meeting, hinted that Britain would wash its hands of the consequences.”
In a later cabinet meeting: “The rest of the cabinet, apart from Grey and Asquith [and Churchill], did not believe that Britain ought to intervene simply to support France and that public opinion would not support such action. […] Asquith described Lloyd George as being 'all for peace' but added he was for 'keeping the position still open'.”
Grey later answered to Cambon: “Germany would agree not to attack France if France remained neutral in the event of war between Russia and Germany. If France could not take advantage of this position, it was because she was bound by an alliance to which we were not parties … This did not mean that under no circumstances would we assist France, but it did mean that France must take her own decision at this moment without reckoning on an assistance that we were not now in a position to promise.”
“If Germany offered France neutrality and they did not accept because of their treaty with Russia, then Britain might argue it was absolved from any obligation it might have to France. Such a position would probably have been endorsed by a majority of the cabinet. In their view any British intervention in an European war should not be determined by France but by any violation of Belgium neutrality if Germany did attack France. (Such a position was also far more acceptable to Parliament and the country.) There was always an important distinction between support for France and for Belgian neutrality. The majority of the cabinet did not want to go to war just to support France (and Russia) against Germany (and Austria-Hungary). Grey claimed that he also told Cambon 'as to the question of our obligation to help France, I pointed out that we had no obligation'."
To summarise: There was no unified opinion in the leadership of the UK on this matter. Parliament and cabinet were deeply devided with only small minorities backing an intervention regardless of the situation leading to the war. Belgium's neutrality was indeed the decisive matter on this issue. Without it the field of speculations is wide open. There were economic, military, domestic and diplomatic reasons for staying neutral, but favouring France.
Actually it all depends on the PoD. The second Moroccon Crisis was a turning point in British-German relations: in OTL bad diplomatic moves by then German secretary of the Foreign Office Kiderlen-Wächter mismanaged the situation which was a once in a lifetime-opportunity to gain ground again. Germany was clearly in the right with its protest towards France and a different handling of the affair with open cards towards Britain might have ended quite favourably for Germany. Grey was initially very unhappy with France and only the Panther at Agadir, the silence of the German diplomats and exaggerated demands later let to a change in attitudes - not only of Grey, but also and more importantly of Lloyd George and churchill, up until then quite Germanophile and pro-peace.
Better talks on naval armament controls are another factor which might help establish a better relationship between Germany and the UK.
But even with a very late PoD, (say abandonement of te Schlieffenplan during the mobilisation phase) - as long as Germany is not declaring war first and then at least at the beginning is just holding the line in the west against the French, the probability of the UK staying out of the war is much higher than its entrance. This includes, of course, that the German navy stays put and oes not move against France, too. Without a PoD before June 1911 the UK will have an informal naval agreement with France that they will protect their channel coast against naval attacks. If German armies are becoming a serious threat to French channel and Atlantic ports, a British intervention becomes increasingly more likely.
In the end a note on military matters:
The latest iteration of German war plans for a defensive stance in the west in OTL are from 1912. They saw 3 armies deployed on the French border, each with 5 army corps, and additional 2 army corps with their own command. That made about 35 divisions in the west compared to French 45. The plan thought also that an Italian army with 5 army corps would join Germany there, which might be overly optimistic, but would have brought the divisions on par. Germany would have also enjoyed a strong defensive position reinforced by forts, whereas the French themselves would face the narrow attack corridor. German plans were designed to counter-attack through Luxembourg or where-else it would be suitable after the French moves would have become known. Although pressure on the German armies would have been high, I think that this plan has some value.
Anyway there were also some plans for a straight (counter-)attack on the french fortress line. These attacks would have concentrated on the fortresses of Toul and Nancy.
Kind regards,
G.