Labour has instructed a top firm of lawyers to begin legally-proofing its programme for government so that it is “water tight” against future court challenge.

Party chiefs believe radical policies being proposed by Jeremy Corbyn will make it one of the most targeted administrations in living history.

Certain proposals in particular have been highlighted as likely to attract a particular backlash from vested interests, including Labour’s nationalisation programme and a planned crackdown on dirty money in the City of London.

One Labour source close to the process said: “It was agreed that we would instruct a well-known and respected law firm to begin drafting the legislative programme in order to make it totally water tight and beyond legal challenge.

“It fits in with lots of areas that we want to tackle – what powers we extend to local councils and devolved nations, sectors for nationalisation.

“We want particular laws to clamp down on dirty money flowing through London.”

The move has been made as part of a broader piece of work being led by shadow cabinet office minister Jon Trickett to steal Labour for government.

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On Monday shadow ministers met at an away day to present plans for a leftwing populist legislative programme in readiness for a snap general election.

Mr Corbyn has already spelled out plans to nationalise Royal Mail, railways and some utilities – which would involve the issuance of gilts to buy out shareholders at a price that would be determined by parliament.

But Conservative ministers have claimed the plans would fall foul of the human rights act, while at least one law firm has warned the plans would face strong resistance in the courts.

The National Crime Agency has said as much as £90bn of criminal money is laundered through the UK each year, but Labour is still likely to face tough opposition to plans to tighten rules form the City of London.

At the away day the shadow cabinet set out a draft Queen’s speech of up to 35 bills and a budget intended to focus on living standards and workers’ rights.

As well as the process of legally proofing the programme for government, Mr Trickett’s work has seen the party taking advice from Gordon Brown on how to prepare for government.