John Marek chairs the house committee

An assembly committee, which Dr Marek, the deputy presiding officer chairs, has given the go-ahead for negotiations to begin with a view to buying a �750,000 plot in Cardiff Bay adjoining the site where the new chamber is being built.

It is understood that members of the house committee were concerned about the possibility of a neighbouring development dwarfing their prestigious new �55m home, as the plot has planning permission for a six-storey office block.

The land purchase, if it went ahead, would be the latest in a long line of unexpected costs associated with the new headquarters.

Labour AM Peter Law said a decision to spend so much public money should not be left to just one committee to decide - and called for the matter to be debated by all AMs.

But Dr Marek said it was important that there was a development there that was "in tune with the architecture of the area."

We run a very tight ship in the committee and we're not asking for any extra money John Marek

"We are very concerned about a six storey tower block which could appear next to the building which is why the committee is in favour of perhaps buying this land," he told BBC Wales' Good Evening Wales programme.

There has been a great deal of opposition to the proposed plans.

Earlier former Welsh Secretary Ron Davies said the suggestion that the Welsh Assembly Government should have to pay out to safeguard the chamber from being overshadowed by a rival development was "absolutely ludicrous".

He said the assembly should have called in the application for planning permission, to ensure that nothing inappropriate could be built.

"Everyone knows that the assembly has powers to call in an application, if it considers the scale to be inappropriate," he said.

"I think the question to be asked is why the planning application - if it was unacceptable in terms of planning or design or architecture - wasn't called in 2000, when planning consent was granted."

The Tory leader in the assembly, Nick Bourne, has previously labelled the controversial debating chamber a "monstrous waste of money."

Architecture

The row is over a piece of land adjoining the site

Blaenau Gwent Labour AM Peter Law said he decision to discuss buying the plot of land was "a major disaster in public relations" and reflected badly on the whole assembly, he said.

"Something as massive as this - bearing in mind the views on the new chamber - I would have thought would be referred back to the assembly for some sort of debate."

It is understood that some members of the house committee voted against the proposal.

But Dr Marek said that if the land was bought they could "sell it off to the private sector."

"We run a very tight ship in the committee and we're not asking for any extra money," he said.

"We do have to protect the area, the architecture of the area.

"We can do it by seeking to buy the land - whether we will or not is another matter."