A WESTMINSTER ­committee exceeded its remit by investigating proceedings at Holyrood, a leading QC has claimed.

Jonathan Mitchell, a founding member of the ­pro-independence Lawyers for Yes group, launched a stinging attack on the House of Commons Scottish Affairs Committee after it took evidence yesterday about a row at the Scottish Parliament.

The Westminster ­committee, chaired by Labour MP Ian Davidson, invited Glasgow University constitutional expert Adam Tomkins after he complained he was interrupted by an MSP during a stormy meeting of Holyrood's European committee earlier this month and prevented from finishing his evidence until later in the session.

The Scottish Affairs Committee said it wanted to hear from Mr Tomkins "on the issue of free speech".

In a letter to the committee yesterday, Mr Mitchell rejected the suggestion the academic had been denied freedom of speech, saying the claim was "inconsistent with common sense and reality".

He added: "It is not ­obvious that this is any part of the remit given to your Committee by Parliament.

"Indeed it is obvious that it is not.

"The Committee has no more of a remit to examine proceedings before a Committee of the Scottish Parliament than vice versa.

"It would rightly resent a reciprocal examination as arrogant.

"However, as of course we are all well aware, its purpose in doing so is partisan."

A request by Mr Mitchell to appear before the ­committee was rejected by Mr Davidson last week.

At yesterday's meeting, Mr Davidson said Mr Tomkins had been subjected to "outrageous behaviour" during his appearance at Holyrood.

Mr Tomkins told MPs there was an "unfortunate pattern" among Scottish Parliament committees whose members did not want to be told that elements of the SNP's White Paper were "legally flawed".