Wark Clements produced the highly-acclaimed series on the First World War

The combined turnover of the companies last year was �20m.

They have been responsible for BBC and Channel Four series such as "Scotland's Empire" and "Location, Location, Location".

The chairman of the new company, Alan Clements, said it would be in the "Premier League" of UK broadcasting.

The move will give the companies the scale of operation which is needed to compete with London-based businesses.

Mr Clements told the BBC's Good Morning Scotland programme: "I think it's absolutely essential.

"If you look at the list of broadcast top indies - the top hundred indies in the UK - Ideal World and Wark Clements are almost exactly the same size at 30 and 31 on the list, and together we'll be at 14th or 15th biggest company in the UK."

The agreement between the Scottish companies also helps fend off the prospect of a takeover by a larger competitor.

Mr Clements said: "The really exciting thing for us is rather than being a branch factory of a London company we've actually got a Scottish team in the Premier League."

Wark Clements recently won a deal to televise Scottish Premier League (SPL) football for the Irish digital television channel Setanta Sport.

The overall value of the rights to televise SPL games is �52m, but the backers of IWC Media deny that this was a crucial factor in supporting the merger deal.

Media couples

"It's not so much the type of programme we can do or not do," said Mr Clements, "but the type of business we can be.

Kirsty Wark will be a key figure in the new company

"The new Communications Act of last year allows independent producers to own the intellectual property on their programmes but the companies that are able to exploit that are the ones with the muscle to exploit that and take advantage of that."

The new company brings together two of the most high-profile media couples in Scotland.

Wark Clements is controlled by broadcaster Kirsty Wark and her husband Alan Clements, while Ideal World is controlled by broadcaster Muriel Gray and her husband Hamish Barbour.

Crucial to the venture's success will be the desire of major channels to source output from around the UK.

Mr Clements said: "It's really really important that we can take advantage as a company of the commitment of the BBC in particular and Channel Four to do a certain percentage (of their programme-making) outside London."