EXCLUSIVE By Editor Wayne Veysey

Laurent Koscielny has passed a fitness test in a huge boost to Arsenal ahead of today’s north London derby, Football Insider sources understand.

The defender had been a doubt after sustaining a hip injury in midweek that kept him out of the 5-1 mauling at the hands of Bayern Munich.

But Koscielny is now in contention for a return against Arsenal’s bitter rivals Tottenham for this afternoon’s 4pm kick-off at Emirates Stadium.

Arsene Wenger must decide which two of his three centre-backs to choose from out of Koscielny, Per Mertesacker and Gabriel.

There are some encouraging signs for Arsenal that the treatment room is becoming less congested.

As revealed yesterday by Football Insider, Alex Oxlade-Chamberlain trained yesterday and could make what would be a shock return for the derby.

Oxlade-Chamberlain had been ruled out until after the forthcoming international break by Arsene Wenger after injuring his hamstring in the team’s League Cup defeat to Sheffield Wednesday 11 days ago.

But, as revealed by Football Insider, the 22-year-old England international had not given up hope of being involved against Spurs.

Skipper Mikel Arteta also trained yesterday and is another Arsenal player who could return against Spurs after being sidelined with foot and ankle problems since the Gunners’ 5-2 win over Leicester on 26 September.

Fit again: Alex Oxlade-Chamberlain returned to training today

Fit again: Alex Oxlade-Chamberlain returned to training yesterday

The possible availability of the trio is a huge boost to Wenger after he voiced his fears on Friday that Arsenal’s growing casualty list could derail the team’s Premier League challenge.

The Gunners could not call on 10 first-teamers as they were thrashed by Bayern at the Allianz Arena on Wednesday night.