Lord Fink: Ed Miliband comments 'untrue and defamatory'
The row over allegations that HSBC's Swiss private bank may have helped wealthy clients avoid or evade tax has led to heated exchanges in Parliament between party leaders.
David Cameron accused the previous Labour government of being the "friend of the tax dodger", after Ed Miliband called Mr Cameron a "dodgy prime minister surrounded by dodgy donors".
The Labour leader singled out the former Conservative co-treasurer Lord Fink as having undertaken "tax avoidance activities".
However, Lord Fink has written to the Labour leader to explain why Mr Miliband's allegations were incorrect.
In a statement outside Conservative Central Office, Lord Fink said: "I challenge Ed Miliband to either repeat his allegations outside the House of Commons, or perhaps to withdraw them publically."