Painting a bleak picture of the lives of cops and drug dealers on the streets of Baltimore, 'The Wire' attracted an 8% share of the 11.20pm to 12.20pm audience.
Many more people are likely to have recorded 'The Wire' using Sky + or other personal video recorders.
The launch of 'The Wire' on British TV came as British actor Dominic West (who plays one of the lead characters in the show -- police officer Jimmy McNulty) said that the BBC cannot produce "high end" contemporary drama to rival US television.
He said the schedules were overly reliant on costume dramas such as 'Cranford', which stars Dame Judi Dench.
In an interview on BBC Radio 4's Today programme, which is likely to have angered BBC executives, he said: "If you turn on American TV, there's a huge choice of nothing you want to see and, unfortunately, I think that's the case here now as well.
"I love costume drama, no one does it like the BBC –- no one has the money to do it, first of all and, secondly, Americans don't have the history to do it
"So we do it brilliantly but if you talk to any BBC producers, they abhor the fact... they're dying to do 'The Wire' and hate doing 'Cranford'."
He added: "I thought 'Cranford' was incredible but we don't seem to be able to do contemporary stuff."
The Times gave last night's episode five stars: "The Wire's creator David Simon ensures that by brilliant characterisation, coruscating dialogue and a fidelity to what he sees as the truth, his audience does too.
"Lord Reith, who would have hated it, might have coined his phrase 'inform, educate and entertain' for 'The Wire'."
Channel 4's 'Sex Education Show vs Pornography' kicked off with 2.1m viewers, down 500,000 on the first episode of the previous 'Sex Education Show' series.
The show, which saw presenter Anna Richardson investigating how easy access to pornography via the internet is affecting young people, attracted 9% share of the 9pm-10pm audience. Including Channel 4+1 figures it reached 2.5m viewers.
ITV1's detective drama 'Law & Order: UK' won the primetime slot with 5.4m viewers and a 23% share of the audience. Last night's episode saw Ronnie and Matt investigating a case of arson in a Turkish club, where the doors were padlocked to stop people inside escaping.
BBC One's 'Crimewatch', featuring the cases of a targeted attack that led to the torture of a father of four, and a serial rapist who has evaded capture for 25 years, pulled in 4.1m viewers and a 17.6% share of the audience.
BBC Two's US drama 'Heroes', starring Hayden Panettiere, netted 1.7m viewers and a 7.2% share of the 9-9.45pm audience.
Five's 'Extreme Fishing with Robson Green', following Green as he hunted for bluefin tuna, lobster, striped bass and steelhead fighting fish on America's eastern seaboard, won 1.6m viewers and a 6.7% share of the 9pm-10pm audience.