Online abuse that greeted Olympic cyclist Sir Chris Hoy's comments on independence has been criticised by politicians.

The SNP has joined Liberal Democrat leader Willie Rennie and Scotland Office Minister David Mundell in condemning the comments.

Speaking to BBC Radio 5 Live yesterday, Sir Chris he said does not want to enter the "hornet's nest" campaign.

He said he is a proud Scot who is proud to have competed for Britain but said Scotland lacks adequate training facilities.

Independence would weaken the remaining British team and pose a challenge for Scotland's new national athletes, he said.

"It's not to say it's impossible but it would just be a different challenge," said Sir Chris.

While many online commentators praised Sir Chris's tone and urged politicians and journalists to respect his plea to keep him out of the debate, other comments were seen as abusive.

Sir Chris was called "a traitor", an "Uncle Tom", a "typical Scots Tory naysayer", a "public schoolboy" and a member of "an English dominated national sports program which concentrates on advancing the English cause" on several online forums.

Tory Scotland Office Minister David Mundell said: "The negative and personal tone of the attacks on Sir Chris is shameful and casts the referendum debate in a poor light. This could deliver lasting damage to damage Scotland's reputation abroad and lead to unnecessary hostility here at home.

"Everyone has a responsibility to guard against the independence debate leaving scars that last well beyond September next year.

"I believe it would be helpful if the First Minister and the Scottish Government were explicit in their condemnation of those trying to shout down the views of Sir Chris and others."

Liberal Democrat leader Willie Rennie said: "The Nationalists seek to silence everyone they disagree with. If this is the kind of Scotland we'll get with independence, I am sure even more will reject the Nationalists' plans."

An SNP spokesman said: "We join Willie Rennie in condemning these comments regardless of what party political persuasion they come from. Online abuse has no place in the political debate.

"It's a matter of public record that Nicola Sturgeon has been sent death threats on Twitter, a posting on the No campaign's Facebook page talked about firing bullets into SNP leaders, appalling remarks about Alex Salmond's dad were made on a Labour party website and the abuse directed at Susan Calman was disgraceful.

"All of it must stop, because the referendum debate needs to be a positive one."

A Scottish Government spokesman said: "The debate on the referendum and our nation's future must be a positive one. The people of Scotland deserve no less. We utterly condemn any forms of abuse either on or offline.

"Scottish Government ministers have made clear that everyone involved on both sides of the debate has a duty to conduct themselves properly."