LONDON (Reuters) - Britain will provide 400 million pounds ($500 million) of funding to spur the building of more fiber-to-the-home broadband connections, the "gold standard" of speed in excess of 1 gigabyte per second only available now to 2 percent of premises.

The government said the finance would be targeted at emerging network providers to encourage a ramp-up in the delivery of full-fiber broadband.

"The UK is already a world leader in superfast broadband coverage, but the country is falling behind on the roll out of full-fiber," it said on Tuesday.

The Digital Infrastructure Investment fund will be announced by finance minister Philip Hammond in his autumn statement on Wednesday, the government said, along with more money for fiber broadband networks in partnership with local areas in Britain.

The country's biggest provider, BT (BT.L), has focused on building fiber connections to cabinets in streets and then relying on slower copper for the final link into homes.

It is deploying a new technology called G.fast to squeeze higher speeds out of copper lines and it has said 2 million homes and businesses would have full fiber-to-the-home connections by 2020.

Critics, including Sky (SKYB.L) and TalkTalk (TALK.L) which rely on its network, say the pace and the scale of BT's ambition is too slow and too small, and they want to see it broken up.

Liberty Global's (LBTYA.O) Virgin Media is the other main network provider in Britain. It said last year it would spend 3 billion pounds to connect about 4 million more homes and businesses to its network, which provides speeds of 200 Mbps.

Smaller providers that have emerged in recent years include CityFibre (CITYC.L), Gigaclear and Hyperoptic.

(Reporting by Paul Sandle; editing by David Clarke)