It was 6-6 at the break and the Saints fans were hoping for a repeat performance in the second half to last year, when they stretched a narrow, three point lead to a bonus point 45-0 triumph.

But 12 months on there was no chance of Castres capitulating a second time and even though Northampton were able to overtake them to move into second place, Castres will end their pool 4 campaign with a home clash with table-topping Ulster.

Last season's beaten finalists, Ulster became the first team to qualify for the last eight with their home win over Glasgow Warriors. Round 6 will now determine whether or not Saints, who travel to Glasgow, or Castres can get enough points to challenge for one of the two best runners-up spots to reach the quarter-finals.

All the points on a misty night at Franklin's Gardens came from the boot. Kockott claimed all the points for Castres, while Steve Myler and his replacement, Lamb, landed three apiece for the home side.