Conservative leader David Cameron said the Tories had nothing to hide in nominating a Black Country businessmen for a peerage after he donated money to the party.
During a visit to the West Midlands, Mr Cameron said Robert Edmiston, who runs car importers IM Group in West Bromwich, had done a lot for charity and was also a large donor to the Conservative Party.
Mr Edmiston is one of four businessmen whose nomination for the House of Lords has been blocked by the House of L ords Appointments Commission.
He has donated £250,000 to the Conservative Party and chairs the Midland Industrial Council, which has also donated six-figure sums to the Tories. He has also sponsored the Grace City Academy in Solihull.
On a visit to Solihull, Mr Cameron said: "Bob Edmiston is a very impressive figure in British business and has made large donations to charity - £27 million I believe to African charities.
"He was nominated for a peerage and he has been a donor and that has always been known. The Conservative Party has never made any secret of the fact that it received loans, whilst the Labour Party did."
The Tory leader, who visited a community police station in Solihull, also criticised the Home Office plans to merge police forces and claimed victory over an amendment to the ID Cards Bill, which will delay their introduction until after the next General Election in 2010.
"I think they are a waste of money. The £19 billion would be better spent on putting more officers on the beat," he said.
"With regards to the merger, I think it is a false reform. By creating a regional force you get forces out of touch and at a greater distance to the areas they serve. Police reforms should be more affective, reducing paperwork and getting more officers on the streets."
Earlier in the day, Mr Cameron was pressed by Conservative councillors about the party's stance on the creation of regional casinos.
During a visit to the Ricoh Arena in Coventry, which is pitching along with the NEC at Solihull to become the site of Britain's first super-casino, Mr Cameron said there was a need to see how the first complex fared before others were considered.
Ken Taylor, leader of Conservative-held Coventry City Council, said the development of a regional casino l ocally was crucial to regeneration.
He said: "There needs to be common sense. This is about jobs and regenerating areas of deprivation. It's not just about building casinos.
"When you consider the real potential that regional casinos present for sustainable and market-driven regeneration, the need for seriously reconsidering our current stance becomes urgent.