A progress committee, combining both politicians and construction experts, was suggested in the Spencely Report into the project and was endorsed by a majority of MSPs.

Lewis MacDonald: Heading cross-party group

But setting up the new working group has been dogged with difficulties.

The most notable was when the Scottish National Party refused to allow MSP and Deputy Presiding Officer George Reid to head the new team, arguing that ministers should take the lead.

Under the emerging deal, Mr MacDonald will head the new group along with Shetland MSP Tavish Scott, of the Liberal Democrats.

The nationalists will also nominate a member to serve on the committee but the Tories said they will not participate in the absence of a minister.

The Scottish Executive will second a senior civil servant to the new group - which will begin work next week and will exercise day to day control of the Holyrood project in an effort to avoid any further slippage on cost or time.

Ways forward

The project was originally priced at �40m but First Minister Donald Dewar conceded last year that the figure would be more like �109m.

Current estimates put the figure at between �190m and �230m.

A majority of MSPs voted to carry on with the project after architect John Spencely was called in to suggest ways forward.

Mr Spencely proposed the task force and new options on cost.