Four top-order batsmen got set in largely benign batting conditions after Andrew Strauss had completed the important business of winning the toss on a sunny morning. Only Bell (87 not out) went on to threaten a century, though, in a total of 275 for five by the time bad light and then rain brought an early close.
Bell, who took his career aggregate to 592 against these opponents – and his average almost back up to 200, after a rare first-Test failure at Lord's – shared half-century stands with Kevin Pietersen (64), Eoin Morgan and Matt Prior. England needed his durability in the absence of a dominant contribution from anyone else, on a pitch which played a little more slowly than anticipated and spun prodigiously at a worryingly early stage.
By stumps, Bell had hit nine fours and a perfectly-executed six over long-on off Abdur Razzak from 171 balls to put himself within sight of his third Test hundred against Bangladesh.
Shafiul Islam struck twice in consecutive overs this morning to undermine England's hopes of undisputed domination against a team they lead 1-0 in this two-match series.
There was rich promise of runs for the taking. Yet after a seamless stroll to 44 without loss, Strauss and then number three Jonathan Trott fell in quick succession.
Opener Cook also went before lunch, leaving Pietersen and Bell together for a necessarily cautious quarter-hour in which they at least closed out the session without further losses.
It was in early afternoon that Pietersen upped the ante with a series of expansive shots against the Bangladesh slow left-armers, who have caused him so many problems in recent months.
He and Bell rattled up 50 runs in ten overs immediately after lunch, Pietersen hitting five of the six fours in his 73-ball half-century in that passage of play.
But slow left-armer Shakib Al Hasan was to have the last laugh on England's most mercurial batsman. Pietersen, evidently determined to impose himself, was stumped by yards after going down the wicket and failing to get to the pitch of a ball that turned sharply.
Strauss had earlier edged some well directed full-length swing from Shafiul to second slip, and the seamer again profited with the first ball of his over when he took the pace off for a cutter that snaked between bat and pad to see off Trott.
After Bangladesh took the field wearing black armbands, because of the fire disaster which has killed more than 100 people in Dhaka, Strauss and Cook began with a rush of early boundaries off Shahadat Hossain.
Shafiul, sharing the new ball, was more accurate. Any England troubles seemed a world away – until Shafiul had his unexpected impact, and then Cook pushed up the wrong line to Razzak's first delivery and edged to first slip. That meant the onus was on Pietersen and Bell, who were to put on 70 in only 15 overs.
After Pietersen's moment of misjudgment, Bell needed more support – and duly got it from Morgan in a second successive stand of 70. Limited-overs sensation Morgan accumulated with wristy and undemonstrative efficiency as he seeks to establish his Test credentials, until a full-blooded cut at Shahadat was wonderfully well caught by Jahurul Islam – one-handed, diving to his right at gully.
Bangladesh – who had the prescience to pick Razzak as a third spinner, to England's one in this match – were compromised by a calf injury which kept Shafiul off the field for almost half the afternoon session and out of the attack for much longer. That was no help to Prior, who has played long innings in the past but undoubtedly still prefers pace on the ball.
In the circumstances, he did well to keep Bell company – albeit with a little luck, when he edged Razzak between wicketkeeper and first slip on 16 and then survived a confident lbw appeal from the same bowler two runs later. Bell simply stayed put, all the while adding to his record against Bangladesh in a chanceless innings so far.