Ofcom will propose converting an entire Freeview multiplex to DVB-T2 so that up to four free hi-def channels can launch within this decade.

Ed Richards, chief executive of the UK's media regulator, said Ofcom will publish its proposal for re-arranging the Freeview multiplexes during November.

He said Ofcom is in favour of encouraging free high definition TV and is still considering the best use of the analogue spectrum after Digital Switch, but had not been convinced it should be given freely to public broadcasters for hi-def.

Instead, one of the three public service multiplexes would have to be converted to DVB-T2 and MPEG-4, possibly as early as 2009. Presumably, the other Freeview muxes would have to be re-organised to make sure no-one missed out on existing MPEG-2 channels.

Mr Richards told the Westminster Media Forum: "Let me be clear that Ofcom believes that HD offers an exciting improved experience for viewers. We are far from indifferent to HD, but we remain firmly platform neutral and pro-competition in our approach.

"We also remain open to argument and evidence for a non market allocation where there is an identifiable public interest that clearly outweighs the opportunity cost associated with it.

"We are working with the broadcasters and others to ensure that the spectrum they already have is used in as efficient a manner as possible. And here we have a great opportunity.

"For some time now Ofcom has been developing a proposal which would enable us to clear an entire multiplex and convert this to an improved compression and transmission standard. If we can make this proposal work, then there is a very major prize.

"Success would mean not only the doubling of capacity for one universally available multiplex, but also for the first time, a migration path for the entire Freeview platform which would offer an enormous increase in capacity.

"This proposal holds out the prospect of HD services on Freeview, using existing capacity, as early as late 2009 and at far lower cost than any alternative proposal."

Of course, that last statement might not be entirely true - it would minimise the cost to the Treasury because they wouldn't lose any funds from the sale of former analogue spectrum

It would also minimise the cost of setting up transmitters for a new Freeview multiplex - which could be significant.

But it seems unlikely that the current roster of Freeview channels could be maintained, without reducing their broadcast quality or axing 'inefficient' uses, such as +1 channels.

Watching anything on the DVB-T2 multiplex would also require a new set-top box, but that shouldn't come as much of a surprise to readers of Save Freeview HD.