Politicians and pressure groups said it was "unethical" for Kenneth Clarke, Sir Malcolm Rifkind and David Cameron to continue to take cash from private companies working in "questionable" fields while vying for the leadership of their party.
Mr Clarke, the former chancellor faced calls last night to donate to charity the £150,000 annual salary he is paid by British American Tobacco, the second largest tobacco firm in the world.
Mr Cameron was called on to sever links with the late-night bar and nightclubs company Urbium, which pays him £27,500 a year as a director.
And Sir Malcolm was urged to drop his £29,000-a-year directorship with ArmorGroup, a company that provides security by ex-military personnel abroad and arms training in the United States.
The international security firm has more than 1,000 armed personnel working in Iraq, and another 1,000 in Afghanistan. It also provides firearms training to "US government clients".
All three contenders said yesterday they would give up their posts with commercial companies if they became leader.
Norman Baker, the Liberal Democrat MP, said: "The leadership contenders' connections with companies working in questionable fields will remind people of the years of Tory sleaze. If they want a new Tory party that is sleaze-free they should drop their connection with these firms immediately."
The three contenders for the leadership are paid for the private directorships on top of their £59,000-a-year MPs' salaries. The directorships are declared in the register of MPs' interests and they are not breaking rules by taking the money. But charities say that working for firms linked to late-night drinking, the cigarette trade and weapons-training raised issues about their judgement.
Deborah Arnott, director of Action on Smoking and Health (ASH), said: "Selling cigarettes is simply unethical - it's not like any other business, these are consumer products that kill when used as intended. He should resign now and give all the money he's received from BAT to charity."
David Davis, seen as the front-runner for the leadership, has no links with any private firms. His right-wing rival, Dr Liam Fox, declares his shareholding in Arrest Ltd, a medical education agency.
Mr Clarke declares six paid directorships, worth some £400,000 a year. They include deputy chairmanships of Alliance Unichem, the pharmacies chain, and British American Tobacco. He is also a non-executive director of the Foreign & Colonial Investment Trust and Independent News and Media. Mr Clarke is non-executive chairman of Savoy Asset Management Group, and British American Racing (Holdings Ltd).
Sir Malcolm. a former foreign secretary, has severed links with several firms recently, including Ramco Energy. His spokesman said he would hang on to his role as director of Aberdeen Asset Management and as chairman of ArmorGroup - which he described as an "extremely ethical company" - unless he was elected leader.
ArmorGroup said yesterday it was "extremely pleased" to have Sir Malcolm as non-executive chairman. "He brings a high level of energy to the board table which is of great benefit to the company as we respond to the increased demand for high quality security services around the world," said a spokesman.
The candidates and their interests
* DAVID CAMERON
He is a director of the late-night bar and night club business Urbium, which runs bars such as Sugar Reef in Soho and the Tiger Tiger chain. The bars have been criticised for lobbying local authorities to obtain 3am licences. The bars are frequented by many premiership footballers and celebrities.
Salary: £27,500 a year.
* KENNETH CLARKE
The former chancellor of the exchequer earns about £400,000 a year from his six directorships. He is deputy chairman of British American Tobacco, the world's second largest tobacco firm, which has been criticised by the health lobby for its role manufacturing cigarettes.
Salary (from BAT): £150,000 a year
* SIR MALCOLM RIFKIND
The former foreign secretary, who opposed the Iraq war, is non-executive chairman of ArmorGroup, a security company which provides thousands of armed guards in Iraq and Afghanistan. It supplies former soldiers and logistical experts, including mine clearance personnel, and firearms training.
Salary: $56,000 (£30,400) a year.Reuse content