The six-part crime drama, in which actors Andrew Buchan and Peter Mullan play members of a band formed to kill criminals who have escaped the law, earned a 26.5% share of viewing on its debut.
It opened with 6.7m though by the last quarter hour only 5.7m were watching while the 'Traffic Cops' audience increased from 3.7m to 4.8m, averaging 4.2m and an 18.2% share.
ITV1 will hope the new series will erase memories of its previous Monday night offering , which limped through its six-part debut series. The fictional romp about a British royal family started with 4.3m viewers and ended with 3.1m.
BBC Two outperformed Channel 4 at 9pm with 'White Girl', part of its special season on the white working class. The 9pm-10.30pm drama about an 11-year-old white girl who turns to Islam after her family is rehoused in a Muslim area of Bradford was watched by 2.3m and earned a 10.4% share.
Channel 4 managed 1.7m viewers and a 7% share for its 9pm-10pm concluding part of science documentary 'Stephen Hawking: Master of the Universe'. Including the Channel 4+1 audience, the programme's figures were 1.8m and 7.7%.
The second outing of Five's series 'Breaking into Tesco', in which cooks compete to get their food stocked by the supermarket, was sharply down from to 1m, giving it a 4.3% share.
Earlier in the evening Delia Smith's return to television for the first of six half-hour shows on BBC Two demonstrated her enduring popularity as 3.7m tuned in, accounting for 14.7% of the audience. 'Delia' was second only to 'Coronation Street', which drew 9.7m and 38.4% to ITV1.