LONDON: Britain's 'Big Four' network rivals - the BBC, ITV, Channel 4 and Five - have signed a non-binding agreement brokered by regulator Ofcom.

Under the deal's terms the quartet will cooperate in the use and development of new HD broadcasting technology on the Freeview free-to-air platform.

If all goes according to plan, the first three HD channels will launch from late 2009, with Five HD airing at a later stage when its technology is ready.

So far as the BBC is concerned, the pact will require the approval of its governing trust - although it is unthinkable that this has not already been the subject of a 'gentlemen's agreement' with Ofcom.

Data sourced from BrandRepublic (UK); additional content by WARC staff