The corporation set up a £603m Digital Switchover Help Scheme (DSHS) to assist elderly and vulnerable people to convert their analogue TV equipment to digital as the switchover advanced across the UK.
On Wednesday, the switch was completed in London as analogue BBC One, ITV1, Channel 4 and Channel 5 were turned off, and Freeview signals boosted in their place for around 4.5m homes across the capital and surrounding counties.
More than 80% of the UK has now made the switch to digital TV and that will rise to 98.5% by the end of the process, in Northern Ireland on October 24.
The switchover help scheme has assisted around 1.2m households, but the BBC expects to return almost £300m of the £603m fund to the government, the top end of previous DSHS estimates of £250m-£300m.
Under the scheme, over-75s, the blind and partially sighted and people with other serious disabilities could apply to get free help to convert one TV set in their home.
But the £603m budget was allocated at a time when digital TV takeup was slower, and it has been found that many homes have already made the switch on their own.
The surplus funds will go towards broadband infrastructure roll out, particularly to rural areas, along with culture secretary Jeremy Hunt's controversial plan to roll out a new generation of local TV services across the UK.
As part of the £630m five-year switchover process, the Crystal Palace TV transmitter in London switched off analogue BBC Two on April 4, leading to 31,000 calls to switchover body Digital UK.
Despite a major marketing campaign, many viewers were confused about the loss of TV channels and the need to return their equipment to regain services.
Transmission firm Arqiva then welcomed BBC director Mark Thompson shortly before midnight on Wednesday to switch off the remaining analogue channels at Crystal Palace.
The final regions to switch will be Kent, the north-east of England and then Northern Ireland on October 24.
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