After dominating the first two days, England allowed Sri Lanka to rack up a second-innings 457 thanks to Angelo Mathews' 160 and stout resistance from the tail.
That left England chasing a record 360 to win and take the series 1-0, but they closed on 57 for five as their top order collapsed. "Ideally we would like to be one or none down and it's a desperately disappointing day," Bell admitted. "It was a really poor one. From the position we were in - we were outstanding for the first two days - we should be better.
"We had chances to stretch the lead and in Test cricket when you play against quality teams if you don't bury them they come back at you and they showed us how to keep you down. They bowled really well but there are no excuses."
Sri Lanka's late surge was built on Mathews' brilliant knock and topped off by Dhammika Prasad's four for 15. "After the first couple of days we never thought we would be in this position," Mathews said. "I was just trying to be positive. We look to score runs. We had to counter attack and whenever we got loose balls, we wanted to score. We stayed positive.
"It will be a positive tour for us if we can win but the job is only half done. We need to take five wickets and will stick to our basics."
After Sri Lanka were finally bowled out, Alastair Cook needed a credible riposte but instead, in two hours of faulty England batting, he was the first to run into trouble.
The captain has now gone 24 Test innings without a century after under-edging a pull at third-change seamer Prasad, who also took a wicket in the very next ball, Gary Ballance lbw for a duck to an brilliant inswinger. Robson then speared an edge to second slip, before the same bowler produced a beauty to bowl Bell through the gate. Plunkett summed up England's miserable day by plonking the last ball straight into the hands of extra-cover off Herath.
Earlier, Mathews, adding his highest score to career-best first-innings bowling, shared stands of 92 with Mahela Jayawardene (79) and then a remarkable 149 alongside Rangana Herath for the eighth wicket.
Mathews drove especially well off pace and seemed a step ahead of England throughout, with their only success came Herath's run-out from the final ball before tea.
England had little to cheer in the morning either as Sri Lanka accumulated 97 runs for three wickets up to lunch - although Liam Plunkett did put himself on a hat trick, making short work of Dinesh Chandimal and Prasad to take his match haul to nine wickets. But James Anderson (three for 91) had been curiously short and often wide rather than attacking off stump with the new ball, and Jayawardene was dropped at gully by Bell off Stuart Broad. That missed chance cost nothing, as Anderson pitched the ball up in his next over and Jayawardene edged a drive, without addition, having hit eight fours and held England up for 168 balls.
There was to be no such resistance from the next two batsmen as Plunkett went short to better effect, Chandimal pulling straight to deep square-leg, and Prasad's upper-cut at the next ball was very well-caught by a tumbling Joe Root at third man.
Mathews had failed to cross on the first occasion, but managed to do so second time he had little difficulty dealing with the hat-trick ball. Herath proved the perfect foil to his captain as the afternoon stretched on, until Mathews called for a single to mid on off Moeen and Root's direct hit easily beat the tailender's retreat. Mathews' innings ended in anti-climax, chipping a full toss from Anderson to midwicket. But England's suffering was not done.
Shaminda Eranga went on to club four boundaries England could ill afford in a last-wicket stand of 20 which ended when Anderson yorked No.11 Nuwan Pradeep, for a first-ball duck. More misery is almost certain to follow this morning.