David Cameron is to announce that under new rules firms that aid tax evasion will be held criminally responsible, as he faces MPs following a row about his investment practices.

The new legislation, which is expected to be contained in the Queen's Speech in May, will mean firms will be held liable if they fail to stop their employees from facilitating tax evasion.

The Prime Minister will be hoping to draw a line under the Panama Papers row, which has seen his finances scrutinised; first over an investment he made in his father's offshore fund Blairmore Holdings; and then over a £200,000 gift given to him by his mother.

The move comes ahead of an international anti-corruption summit in London on May 12 and follows the announcement of a new task force aimed at investigating the evidence from the Panama Papers data leak.

Proposals for the measure were announced in March 2015.

Awkward timing

The London anti-corruption summit had been planned long before the leak of 11 million documents from Panama law firm Mossack Fonseca thrust the issue of tax dodging back into the spotlight.

The Prime Minister has used a series of international gatherings to push for action on corporate transparency, which is one of the reasons the affair has proved embarrassing for him.

The Panama Papers leaks included details of Blairmore Holdings, the firm set up by his father - which until 2006 used "bearer shares" to protect clients' privacy - and which David Cameron and his wife had an investment in until they sold their stake for £30,000 in 2010.