Lord Attenborough speaking at the Pop Factory in Porth, Rhondda

Progress on the complex near Bridgend halted last July amid problems over sewerage plans, and bad weather means work will not resume fully until March.

But Lord Attenborough said companies were keen to cut costs in Wales.

He said: "People are coming to me saying 'When, when, when?'".

Lord Attenborough, the 83-year-old Oscar-winning actor and director, was at the Pop Factory media complex in Porth, Rhondda, on Friday night to re-launch the Rhondda Cynon Taf business club.

He told the invited audience how the Dragon scheme, dubbed Valleywood, would "build studios that have not been seen for decades throughout the world".

If you say to somebody, come here to south Wales, you can have all these open spaces, you can breathe clean air, it's very seductive Lord Attenborough

The development began construction in earnest last July after five years of planning.

Organisers say the 12 state-of-the art sound stages and TV studios will make south Wales a centre of the UK film industry.

But within days of Lord Attenborough posing for the cameras as the bulldozers moved on to the site of a former opencast mine, work ground to halt while the necessary permits for sewerage work were gained.

'Agony of London'

On Friday, he and business partner Stuart Villard explained that the delay had taken until last October to resolve, by which time the building work was hit by bad weather.

They said work would not start again entirely until March, with completion of the first two film studios set for the late summer.

The 12-studio complex will offer filmmakers a new location

Lord Attenborough said film production companies continued to find the idea of moving their projects out of London to south Wales "very seductive".

He said: "Working within the M25 is really costly now.

"The costs in London are horrendous. The costs [in Wales] are much lower.

"But it's not only the costs [of London], it's the conditions, the agony of moving around, the misery of getting anywhere.

"If you say to somebody, come here to south Wales, you can have all these open spaces, you can breathe clean air, it's very seductive."

Dormice

Mr Villard said the first two studios to be finished would be 20,000 sq ft and 10,000 sq ft.

He added: "We could let 10 stages right now, and that's no exaggeration."

The project's website claims film makers can save up to 25% on their multi-million-pound budgets by switching their operation from London to south Wales.

The Valleywood complex aims to bring 12 studios, including one of 30,000 sq ft and two of 20,000 sq ft to provide facilities for recording anything from a quiz show to a big screen blockbuster.

A new motorway junction is included to provide access from the M4.

Construction work had previously been held up for four months while investigations ensured the development would not harm any of the dormice population.