It all looked so promising when goals from Stephen Clemence and Sergei Reborv put Colin's side two goals to the good after just over half an hour. Thick fog then descended and the previously solid performance became somewhat chaotic.
John Robinson pulled one back for Charlton just before the break following a defensive mix up and shortly after the interval a disputed penalty was struck home by Chris Bart-Williams. Robinson hit the winner with a low drive from distance on 77 minutes.
"The first half was excellent and we deserved to be a goal or two up," reflected Colin. "We had a real good opportunity to make it three and, if we were really clinical, we might have done.
"After that a mistake gifted them their first goal and the boys are adamant he wasn't pulled for the second one. That got them back in the game.
"From that point onwards they were more energetic than us and they worked really hard and made tackles - we didn't.
"In the opportunities we did have to use the ball we weren't as clinical and as good as we had been in the first half."
Colin refused to use the thickening fog as an excuse, pointing out that Charlton did not seem to find it a problem.
"I think you've got to be able to see both sides of the pitch and there were occasions when we couldn't see where the ball was going. Difficult for the players, but they did alright in it and we didn't. You can't blame the conditions for that.
"We weren't as cool, calculated and clinical as we should have been and it's a real let down after 40 minutes of good football."
Colin Calderwood saluted a first half of excellent football by his reserve side against Charlton at Stevenage but lamented a second period display that saw the visitors run out 3-2 winners.