But Alex Barr, who works for Scotland's largest PR agency Beattie Media, said he later insisted it would be "immoral" to promise access to government ministers.

BBC Scotland Political Editor Brian Taylor reports

Mr Barr was giving evidence to the Scottish Parliament's standards committee's investigation into The Observer newspaper's claim that the agency said it could arrange meetings with ministers.

The newspaper secretly filmed a meeting with Mr Barr and another Beattie employee, Kevin Reid - son of the Scottish Secretary Dr John Reid.

Mr Barr was questioned by committee members on Friday along with Mr Reid, Beattie Media boss Gordon Beattie and two journalists from The Observer.

The next step in the investigation will take place in a fortnight's time - after the parliament's recess - when it is expected that Finance Minister Jack McConnell's diaries will be examined.

Members have also requested to see a full Beattie Media client list.

'Deep regret'

Reading from a prepared statement, Mr Barr said he "deeply regretted" the impact the controversy had had on everyone involved.

The same words of apology were read to the committee by Mr Beattie.

The firm's boss also took the opportunity to criticise The Observer referring to its undercover reporting as a deliberate "sting".

He was stopped halfway through his statement by committee member Tricia Marwick who said: "We should not allow a rant against The Observer by Mr Beattie."

Gordon Beattie called The Observer investigation a "sting"

When he was given permission to carry on, he returned to his notes and outlined what he believed was The Observer's real motive.

He said: "The paper wanted to entrap the son of the Secretary of State for Scotland and thus embarrass him and Beattie Media."

Mr Beattie was questioned for 40 minutes about his firm's recruitment policy and his personal contact with Finance Minister Jack McConnell - a former Beattie Media employee.

Alex Barr reads his statement to the committee

In an earlier session, Mr Barr told the committee that he was so concerned following the meeting with the undercover journalist that he wrote to him on the same day to make his company's position clear.

He added: "I also made it clear in my letter that it would be both unprofessional and immoral for any public relations consultancies to promise access to ministers."

Mr Reid (left) and Mr Barr's meeting was filmed

Questioned by the committee, Mr Barr said he thought he had been in a competitive situation, bidding for business against other agencies. This, he conceded, had made him "over-state" his company to the prospective client.

"I went to sell public relations and not public affairs and if there's been any dubiety caused as a result of that, then that's the explanation," said Mr Barr.

When asked about his links with Mr McConnell, Mr Barr said he had several contact numbers for the minister, including a pager, and read one of the numbers to the committee.

Mr Barr also agreed several times to hand over his entire personal contacts book for the committee to scrutinise.

Former Labour worker

Mr Reid outlined his recollection of The Observer's undercover filming before the committee.

He said: "I explained who I knew and I explained, or what I was trying to explain, is that it doesn't go against me that I used to work in the Labour Party.

Kevin Reid faces questions from James Douglas Hamilton

"It gives me an understanding of political issues, it gives me an understanding of the politicians, it doesn't mean I provide access."

The Observer's Scotland Editor, Dean Nelson, said the investigation began after the newspaper was approached by concerned politicians.

He said Beattie Media was targeted because it had employed Dr Reid's son although he had no previous experience of lobbying.