The Queen's Christmas Broadcast was the most watched TV programme on Christmas Day, according to overnight figures.
But Call the Midwife ended up the most watched programme overall once on-demand figures were calculated.
Overnight figures revealed a combined audience of 6.4 million watched The Queen's annual message on BBC One, ITV, Sky One and Sky News.
That figure rose to 7.1 million once figures were consolidated - less than Call the Midwife's 8.7 million total.
The Barb figures show a continuing decline in Christmas TV viewing - 7.6 million watched the Queen last year.
Michael McIntyre's Big Christmas Show on BBC One initially seemed the highest-rated programme on a single channel, with overnight figures putting its audience at 6.1 million viewers.
Yet even when its figures were consolidated, its 7.6 million viewers only saw it claim second place on the festive viewing rundown.
The overnight figures mentioned include people who watched a programme live or on catch-up on TV before 02:00 GMT on 26 December.
But they do not include those watching on-demand services on smartphones and computers, figures that are added later to obtain a total, "consolidated" figure.
The Queen used her Christmas broadcast to say that the Christian message of "peace on Earth and goodwill to all" was "needed as much as ever".
Zog, the BBC's animated version of Julia Donaldson's book, ended up fifth on the viewing chart with a consolidated seven-day audience of 6.9 million.
By Lizo Mzimba, entertainment correspondent
The BBC may have, as usual, dominated this year's ratings - but traditional TV viewing on Christmas Day is falling significantly.
Ten years ago, Wallace and Gromit: A Matter of Loaf and Death was watched by an overnight audience of 14.3 million people. That's more than double the number who watched this year's highest rated programme, The Queen's Christmas Broadcast.
Even solid performers like Mrs Brown's Boys lost large numbers of viewers compared with 2017. The comedy is down by more than 2 million year on year.
The growing impact of streaming services like Netflix and Amazon is undoubtedly partly to blame.
It's likely that a lack of "event programmes" that can deliver really big in the way that shows like Only Fools & Horses did, has also contributed.
But the most significant factor is probably a very straightforward one - people's viewing habits are changing, and TV viewing on Christmas Day is becoming less important to us.
While the traditional image of families settling down to enjoy a variety of festive TV together is still an accurate one for many, for more and more people TV is no longer the automatic choice on Christmas Day.
Audiences for Christmas Day have been falling in recent years and no programme has attracted more than 20 million viewers since 2001.
The single biggest Christmas Day TV audience was recorded in 1989 when 21.8 million watched the UK premiere of the film Crocodile Dundee.
The official figures do not include repeats - ruling out the late-night episode of EastEnders broadcast on Christmas Day 1986 featuring "Dirty" Den Watts handing divorce papers to his wife Angie.
The programme had an audience of 30 million if a repeat on 28 December is included, but only 18.9 million watched it on 25 December.
Top 10 most-watched programmes on Christmas Day 2018
1. Call the Midwife (BBC One) - 8.7m
2. Michael McIntyre's Big Show (BBC One) - 7.6m
3. Strictly Come Dancing (BBC One) - 7.5m
4. The Queen's Christmas Broadcast (BBC One, ITV, Sky One, Sky News) - 7.1m
5. Zog (BBC One) - 6.9m
6. Mrs Brown's Boys (BBC One) - 6.7m
7. Coronation Street (ITV) - 6.7m
8. EastEnders (BBC One) - 6.5m
9. The Jungle Book (BBC One) - 5.5m
10. Emmerdale (BBC One) - 5.4m