Datafile - Exposure: 01.09.07.

Amy Winehouse's first number one radio airplay hit, Tears Dry On Their Own, spends its fourth week at the airplay chart's summit, overcoming a modest decline in support to record a 7.5% victory margin over new runners-up Plain White T's debut hit, Hey There Delilah.

The latter title's 3-2 move is attended by fairly modest 5.6% hike in its audience and a tally of 806 plays, compared to its previous frame total of 749 - and it's hard luck on KT Tunstall, whose Hold On swaps places with it, despite the fact it registers the biggest increase in plays on any song on the chart.

Hold On jumps from 771 plays to 1,145, but manages to lose 17.18% of its audience along the way. That is mainly a consequence of reduced support from the three stations that provide its biggest audiences - Radio One, Radio Two and Virgin where, respectively, its plays fall 17- 11, 20-16 and 43-31. The consequent loss of audience more than wipes out its substantial gains elsewhere.

One of the biggest climbers on a fairly quiet week is Maroon 5's Wake Up Call, Aiming to emulate its predecessor, Makes Me Wonder, which spent three weeks at number one, Wake Up Call ...