This website makes some claims about what has caused both growth and decline that are pretty contentious.
I think that many would argue that the growth following the second world war was the result of massive state investment in public services like creating the NHS and the building of council housing.
They baffelingly attribute yhat growth to the Conservative Govrernment of the 1930s rather than the post war labour government.
Similarly this page attributes growth in the 80s to the Conservative government privatisation program. Again many would argue that was actually the start of the decline which we are feeling the pain of now with things like a terrible and fractured rail service and not enough housing.
I think a perfect example of this is our water companies that have been private since the 80s and have done nothing but pay dividends to shareholders and now we have a disaster with shit being poured into all our rivers and costs to households rising dramatically.
Edit: I read on and they use the drop in passengers in the railway in 1965 as an argument against nationalisation of the rail service, somehow neglecting to mention the beeching cuts! That is incredibly missleading given 55% of stations were axed due to a /reduction/ of state infrastructure at that time.
Historically yes it is a massive part of what unions have done and continue to do. For example there have been many examples of dock workers refusing to transport South African or Israeli goods. That this is done as a collective action organised by union is what protects workers from individual retaliation.