TO all but the most square-eyed telly addict, they sound like a gaggle of foxy superheroines or a hastily-assembled girl band. But Diva, Faith, Angel and Minx are the latest members of what looks like becoming an exclusive club.

They are four television channels that in the past two months have joined some 600 others jostling for eyeballs on BSkyB’s electronic programme guide (EPG). The number rises to 1,000 with regional variations and interactive services.

The launch of digital stations seems endless – recent entrants include Nuts TV and Dave. But after a spell of explosive growth, the EPG is reaching its capacity.

That means broadcasters face having to pull out their chequebooks if they want to get on air in the future. And for tiny channels already on the platform but bumping along with little or no advertising income, it could be time to cash in as the opportunities for trading channel slots take off.

Many of the best-positioned berths – those nearest the top of the EPG – are potentially worth several million pounds.

Channel 4, 25 years old this week, has already been busy. In the summer, it bought three slots from Life TV, a small competitor and neighbour on the EPG, paying in the region of £2m.

The deal means it is able to create a bank of six channels in a row, including a soon-to-be-launched high-definition service. Corralling stations together in such a way is invaluable in the multi-channel jungle.

Channel 4 estimates that catchup services such as E4+1 boost ratings by up to 30% – as long as viewers know where to find them.

Separately, the shopping channel JML recently opened its purse to buy two positions that vault it to the top of its category listing.

The capacity problem is one of technology. Sky, which is 39% owned by News Corporation, ultimate owner of The Sunday Times, carried 200 channels when it went digital in 1998. A threefold increase since then put millions of older set-top boxes in danger of struggling to cope. They have limited memory compared with the latest Sky Plus equipment.

Since it was launched, Sky has operated as an open-access platform. Any channel that gains a licence from regulator Ofcom can join the queue for a slot.

It has not been short of applicants. Until the summer, four channels were being launched on Sky every week. That has slowed to two a week, but most of the 100 channels on the Ofcom waiting list will still miss out.

Richard Brooke, corporate development director at the sports broadcaster Setanta, said: “It’s okay for those that are already in the castle now that the bridge has been drawn up. But we need to have flexibility. Setanta is an expanding organisation so we still need to have slots to launch new channels.”

Setanta is at present recycling one of its existing slots on Sky to launch Setanta Sports News.

Sky is proposing to relax its own rules on channel trading, such as the 28 days’ notice of any change of control.

Some lay the blame for the capacity squeeze at the door of Ofcom, which said it was “assessing and monitoring the situation”.

“This was a train wreck waiting to happen,” said David Hulbert, until recently chief executive of Sparrowhawk Media, broadcaster of the Hallmark Channel outside America.

“It seems to me that the regulator has treated Sky as a public utility in open access. Realistically, whenever you tout something as being pretty free it fills up. It is just too attractive for people who don’t have a business model.”

Capacity does not affect rival Virgin Media in the same way. It can pick and choose who it allows on to its 120-channel platform.

With the switch-off of the analogue TV signal set for 2012, capacity constraints are prompting some hurried conversations. ITV chairman Michael Grade wants enough spectrum to be allocated to Freeview so it can carry high-definition channels, which gobble up bandwidth.

Ofcom boss Ed Richards is so far unmoved, arguing that compression technology could squeeze more on to the platform in a couple of years.

No wonder Freeview slots, controlled by the BBC, ITV and National Grid, are worth at least £10m each.

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