Britain's former prime minister David Cameron and financier Lex Greensill will face long-awaited questions from lawmakers next week about claims of improper government lobbying, parliament said Friday.

Cameron advised the Australian businessman's firm Greensill Capital and sought government support for the stricken company last year by texting finance minister Rishi Sunak, bypassing official channels.

Former British prime minister David Cameron has admitted he acted in error but denies any impropriety Former British prime minister David Cameron has admitted he acted in error but denies any impropriety Photo: AFP / PHILIPPE HUGUEN

Cameron, who was prime minister from 2010 until he resigned after Britain voted to leave the European Union in 2016, has admitted he acted in error but denies any impropriety.

Greensill faces questions at the powerful Treasury Committee next Tuesday while Cameron follows on Thursday, according to the UK parliament agenda published on Friday.

Committee chairman Mel Stride said the body is determined to discover whether Britain's finance ministry "responded appropriately" to all lobbying on the firm's behalf.

Greensill filed for insolvency in March Greensill filed for insolvency in March Photo: AFP / Oli SCARFF

Greensill Capital filed for insolvency in March. Its clients included steel magnate Sanjeev Gupta's Liberty Steel, which employs thousands of workers around the world.

Current Prime Minister Boris Johnson ordered a senior lawyer to investigate Cameron's lobbying for the firm in April.

That inquiry comes as his ruling Conservative government faces broader allegations of cronyism and a lack of transparency.

In recent months it has emerged that firms with government contacts were more likely to be awarded contracts for supplying personal protective equipment during the coronavirus pandemic.

A row over text messages with billionaire businessman James Dyson and who paid for the costly renovation of the prime minister's official residence have further fuelled "sleaze" claims against Johnson's government.