A millionaire ex-Tory party treasurer with links to a high-interest loans company has been knighted in the Queen’s Birthday Honours List, as others who donated to the Conservatives during the election are also recognised.

The Swiss-born multimillionaire banker Sir Henry Angest, one of the Tories’ biggest financial backers, received a knighthood “for political service”. The fact that he has channelled almost £7m to the Conservatives in loans and donations has raised fresh concerns that the party is using the honours system to reward its donors.

As chairman and chief executive of the Arbuthnot Banking Group, Sir Henry is also behind Everyday Loans, a company charging members of the public an average of 74 per cent APR.

Also knighted is Sir Michael “Mick” Davis, whose donations to the Tories total £1.4m, and who gave £160,000 during the election. The Honours Committee said his knighthood was for his work chairing the Prime Minister’s Holocaust Commission.

Another Tory donor, Jeremy Isaacs, who has given a total of £416,500, including £25,000 during the election, was made a CBE for his work with Imperial College NHS Trust in London.

As news of the awards emerged last night, the Labour MP Graham Jones warned: “People will be rightly concerned if it emerges that the Tories are rewarding their donors with honours.”

The most controversial of all today’s honours is Sir Henry’s knighthood, given his connection to a company offering high-interest loans. Everyday Loans was acquired in 2012 by the Secure Trust Bank, which is owned by Arbuthnot and has Sir Henry as its non-executive chairman. Although an Arbuthnot spokesman insisted it was not a payday loans company, because it only offered loans over periods of 13 months or more, its current average APR is 74.4 per cent.

Sir Henry’s link to Everyday Loans emerged in 2013, embarrassing the Conservatives at a time when the Government was promising to crack down on high-interest lenders. With his wealth estimated at £135m by the Sunday Times Rich List, Sir Henry has given the Conservatives a total of £1.9m in donations, either personally or through his companies.

He is a member of the Leader’s Group, described by the Conservatives as the party’s “premier supporter group”.

A Conservative Party spokesman insisted last night: “Volunteering for a political party strengthens our civic democracy and contributes to public life. It is quite right we recognise long-standing contributions, just as we do for other types of public service.

“All nominations for honours are assessed on merit by one of the nine independent honours committees, and must involve a personal commitment even if an individual has made a financial donation.”

The Arbuthnot spokesman said Sir Henry did not wish to comment.