RTE has said it regrets that one of its most senior television executives has resigned less than a year after she took up the position.

Ms Helen O'Rahilly, who was appointed as director of television production last summer, is leaving the station to rejoin the BBC, as editor of its documentary and history channels on its new digital network.

This is the second blow to the station in a week.

RTE said yesterday it would seek an "urgent meeting" with the Minister for Arts, Heritage, Gaeltacht and the Islands, Ms ile de Valera, to discuss suggestions that she is to sell off its transmission network to the highest bidder and exclude it from the company which is to set up the State's digital network.

Ms O'Rahilly replaced Mr David Blake-Knox, who left RTE in November 1998, also to join the BBC. She joined RTE as a researcher in 1986 before moving to Britain and was editor of the BBC's Watchdog programme prior to her return last year.

The move comes at an inopportune time for the station as Ms O'Rahilly was involved in sensitive negotiations on a transformation agreement with its trade unions on work practice changes.

RTE's director of public affairs, Mr Kevin Healy, said Ms O'Rahilly's departure was not related to suggestions that the station's Millennium production had under-performed.

While Ms O'Rahilly had responsibility for production of the entire television schedule, he said she "wouldn't have been directly involved" with the Millennium programme.

In a statement, the broadcaster's managing director of television, Mr Joe Mulholland, said he accepted Ms O'Rahilly found it impossible to turn down the offer to rejoin the BBC, where she will take up her new position in early April.

"I very much regret her departure and I know that she will be missed in the television division," Mr Mulholland said.

Asked whether RTE would face a tough challenge replacing Ms O'Rahilly, Mr Healy said: "It's always difficult to find somebody to fill a position as senior as that one."

No decision had been taken on whether to hold a competition to replace Ms O'Rahilly or to do so by internal promotion, he said.

On the future of the transmission system, Mr Healy said RTE had been taken "totally by surprise" by a report stating that Ms de Valera would sell off its network and be excluded from Digico, the proposed joint venture which is to manage the new digital network.

"We want to know how this radical proposal came about," he said, adding that RTE would oppose the sale of its current transmission network.

"We need clarification from her as to what she plans to do."

Before this development, RTE believed it would be allowed take ownership of up to 40 per cent of Digico, which would be set up after the Oireachtas passed a new Broadcasting Bill, Mr Healy said.

"We saw matters proceeding, albeit slowly . . . It would now appear that she's taking a totally different route."

The station was still seeking a strong shareholding in Digico, he said.

"Our priority is the very quick provision of indigenous digital programming. It's vitally important that good quality home-produced content can be produced on the network."

Mr Healy said there had been a "major disagreement" with AIB, which is advising a project management group on the creation of a digital network, on the valuation of RTE's existing network.

"They had a figure and we had a figure and let's just say there was a substantial difference."

Industry observers believe AIB placed a value of about £30 million (€38 million) on the network, while RTE maintained that it could be worth £60 or £70 million, if not more.