I am certainly not a big expert on postwar Britain, but I will have to disagree.
The problem with that was most of the industries nationalised were done so to stop them collapsing.
I don't think any of the British industries nationalized by Attlee was in danger of failing in the 1940s. The coal mines, the railroads, the Bank of England, and everything else nationalized were not in danger of immediately going bankrupt. Attlee didn't nationalize them to "save" them, but because Labor wanted the government to command the heights of the economy and insure full employment.
Britain didn't need to nationalize anything to get "full employment." None of the nations did after WWII. It is not the situation where Britain was a unique case where it would not have done well unless nationalization took place.
I think you may be confusing the nationalizations which took place much later when the British economy had been run down even more (like when the government forced the car industry to merge in the 1960s and nationalized them in the 1970s). If the Labor government in 1968 not forced those companies to merge, some of them would have remained competitive and stayed in business. Instead, the merger failed and became a financial eyesore to ruined the whole sector.
It was necessary with the restrictions placed on Britain by the US. Massive exports were needed to meet US financial demands and hence public consumption inside Britain had to be kept low.
Britain did have crushing debt, and this needed to be serviced. Certainly the initial end of Lend Lease in 1945 caused problems. But the US quickly extended loans to help Britain out, and then there was Marshall Plan funds later. If Britain had planned for the transition better between war and peace (including discussing financial options with the US), even these hiccups could have been averted.
But certainly it did not need to keep wartime controls in order to service the debt. It could have done away with them relatively soon after the war ended. What Britain needed was to end its financial commitments that diverted a lot of money away from this. Some of this has to do with the Empire, or European security (like its aid to the non-communist Greeks), and some of it had to do with the new financial obligations created by Labor's policies. That last bit could have been averted entirely. (Those nationalized industries were inefficient and needed subsidies. In private hands, they would have become more efficient and not needed support. No doubt they'd have let go of some employees, but I think they would have found employment easily in a freeer market in the economic conditions of the late '40s and early '50s. ) The other ones would have been difficult given the mentality of the time, but some form of triage could have been done with the most pressing concerns met, and others abandoned.
In any sense, policies like price controls inevitably create shortages. They don't end them. A more flexible economic policy would have alleviated things, not made them worse.
The problem was that he and possibly the Tories of the time had plenty of their own daft ideas. Opposing investment in health and education especially.
I am sure the Tories had plenty of daft ideas. All politicians do. However, even if investment in health and education was needed, it doesn't mean Labor's plans were the best alternative, or that Britain could not have done well by delaying such investments until after it recovered its finances.
A major problem with British industry was its workforce. Its unions were divided into very inefficient craft unions. British companies needed to negotiate with hundreds of unions instead of just one. Instead of nationalizing indutry, Labor would have done better addressing the real reasons for inefficient labour practices. Of course, that's not what would have been done. Labor was there to accomodate the British labor unions and not challenge them. The wind sown there would be reaped in the 1970s.
Labor's policies of nationalization, wartime controls, and high taxes created the situation where British industry were starved of funds to modernize. In thsi time period, Britain was the government with the highest form of socialism. None of the other European combatants did. They all did better. I don't think that's a coincidence.
The steps taken by the Attlee government did a lot to delay the further decline, despite the harsh circumstances they found themselves in.
I don't see any evidence of that. What are some examples that clearly demonstrate the situation would have been worse? I'm ignorant.
Britain faced a lot of major challenges in the postwar era. A non-Labor government would not have overcome all of them, and it would have made other mistakes.
Clearly, Britain also needed to take a leadership role in the economic integration of Europe. An early leadership role in what would become the common market would have given it benefits of an increased market, and allowed it to develop institutions in a way more favorable to Britain. Being outside the EEC hurt Britain once that area took off economically. Britain needs to be in it (or some version of it). In addition, a rational policy to allow the Pound to be properly valued also would ahve helped matters. The over valued Pound certainly hurt. Britain was spending far too much on military and security. It needs a rational plan to reduce that to levels it can actually maintain. It also needed to change its entire way of industrial labor relations. Above all Britain needs to retool its industries, and we know that Labor's policies won't allow that to happen.
None of these things were easy to do, and much of what needed to be done was apparent only in hindsight.