When William Gallas staged his childish lone sit-down protest atÂBirmingham two years ago there cannot have been many who thought his departure would leave a huge hole at Arsenal.

But as Arsene Wenger tries to fine-tune his squad for the forthcoming season the gap left by the former Chelsea defender is proving devilishly difficult to fill.

Experienced, physically-imposing, quality defenders are hard to come by at a decent price.

That is why the Arsenal manager is still ready to resort to resigning Sol Campbell - even though agreeing to Gallas’ two-year contract  demands when the  club had the chance may have provided better value.

Wenger has taken what he would describe as a gamble in bringing in Laurent  Koscielny, 24, from L’Orient for £10 million.

The 6ft 1in centre back has potential and adds a much-needed more youthful look to the defence, but he also looks lightweight and not quite another Thomas Vermaelen yet.

With Arsenal’s goalkeeper situation another unresolved issue, Koscielny will  be given time to adapt.

Johan Djourou still has work to do after injury last year and Wenger’s squad lacks a central partner on Vermaelen’s level with the season only three weeks away.

Campbell, 36 in September, could still do a job but he does not have the pace of Gallas and is not the answer to an area of the team Wenger sees as a  problem.

The manager has claimed Campbell - also wanted byÂNewcastle, Sunderland andÂCeltic - is in ‘no man’s land’.

But that is where Arsenal will find themselves if top-class reinforcements at the back are not found soon.