I believe there has always been a large amount of corruption in the United Kingdom, but it was hidden very well with at least the pretence of fairness. Especially when under the governance of the old boys or the Public School set.
These, days there is not even a pretence of corruption for favourable businesses, corruption will always be worse under 'Socialists' because they are always personally, looking for someway to benefit from assigning contracts. Thus, why certain famous developers in Manchester always profess to leaning 'Left' Politically, in order to fulfil their development plans. Certain people know there is enough in the deal to ensure Socialists get their cuts, whether financially or politically while ensuring the Unions are firmly onboard.