Channel 4's broadcast of the Leonardo DiCaprio environment documentary The 11th Hour on Sunday night, May 25, was watched by 800,000 viewers.
The UK terrestrial TV premiere of the 2007 film, which was narrated by DiCaprio and analysed the ecological threats to the planet, attracted a share of 4% between 7.25pm and 9.15pm, according to the unofficial overnights.
Channel 4's DiCaprio documentary was beaten by Meerkat Manor on BBC2, which was watched by 1.3 million viewers, a share of 6% between 7.50pm and 8.15pm.
This was followed on BBC2 by new series Ray Mears Goes Walkabout, in which the survival expert travelled to remote parts of Australia.
Ray Mears Goes Walkabout pulled in 2.2 million viewers and a 10% share between 8.15pm and 9.15pm.
The 11th Hour was also beaten by the cricket highlights on Channel Five, which attracted 900,000 viewers and a 5% share between 7.15pm and 8pm, for coverage of England's third-day fightback in the second test against New Zealand.
This was followed by Five News, which averaged 600,000 viewers between 8pm and 8.15pm; and a repeat of the Extraordinary People documentary The Tiniest Boy in Britain, which averaged 800,000 viewers and a 4% share.
The battle for the 8.15pm drama slot was won by ITV1's period police show Heartbeat, which averaged 5.5 million viewers and a 24% share over the hour.
BBC1's The Inspector Lynley Mysteries averaged 4.6 million viewers and a 20% share between 8.15pm and 9.45pm.
Ross Kemp SAS drama Ultimate Force drew 3.5 million viewers and a 16% share on ITV1 over 90 minutes from 9.15pm.
Over on Channel 4 from 9.15pm, the terrestrial premiere of Johnny Cash biopic Walk the Line drew 2.4 million viewers and a 13% share over two and a half hours.
BBC2's Wild China picked up 2.7 million viewers and a 12% share over an hour from 9.15pm, while Five's terrestrial movie premiere Into the Blue attracted 900,000 and 4% between 9.15pm and 11.25pm.
The third instalment of Russia: a Journey with Jonathan Dimbleby attracted 2.1 million viewers and a 12% share on BBC2 over an hour from 10.15pm.
On BBC1, a repeat of the final episode of the final instalment of series eight of My Family attracted 3.4 million viewers and a 16% share in the half hour from 7.45pm.
At the same time, Coronation Street averaged 7.4 million viewers and a 35% share on ITV1.
ITV1's coverage of the Monaco Grand Prix, in which the UK's Lewis Hamilton emerged as the victor, powered to 3.9 million viewers and a 35% share between midday and 3.45pm.
The programme peaked at 5.4 million viewers and a 44% share between 2.45pm and 3pm at the culmination of the race.
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