Godolphin's longest-serving trainer Saeed Bin Suroor had his Stanley House stables in Newmarket visited by BHA drug testers yesterday – although there is no suggestion he has been involved in any wrong-doing.
The regulatory body confirmed yesterday it had extended the testing programme to the entire Godolphin operation.
The move comes in the wake of another Godolphin trainer, Mahmood Al Zarooni, being banned for eight years over doping offences.
Al Zarooni has since left the Godolphin operation, which is headed by Sheikh Mohammed bin Rashid Al Maktoum, ruler of Dubai.
BHA spokesman Robin Mounsey said last night: "We can confirm that, for the sake of completeness, we are conducting testing in training at the yard of Saeed Bin Suroor, although there was no reason to link the two yards because of the common ownership by Godolphin."
Meanwhile, Joseph O'Brien believes Cristoforo Colombo can cut the length deficit on Dawn Approach when they renew rivalry in the Qipco 2000 Guineas at Newmarket tomorrow.
Ireland's champion jockey is convinced the colt was beaten by the draw when third behind the Jim Bolger-trained ante-post favourite and Olympic Glory in the Coventry Stakes at Royal Ascot.
Despite the disadvantage of being drawn on the wrong side of the course, Cristoforo Colombo was only a length behind the winner at the line.
The jockey feels there is more to come from his mount especially when he gets suitable ground. That is one of the reasons he chose the son of the 2008 hero Henrythenavigator over his father Aidan's other runners, Mars and George Vancouver.
"The fast ground will help him and I think he will improve for the step up in trip. He ran a massive race in Ascot last year when he was drawn on the wrong side of the track," the jockey said.
"I was on my own and the first two were on the stands side so I'm hoping for a good run.
"He has cheekpieces on as he can be a little bit lazy in his races and they will help him to travel. He's never had his ground and I think everything is right for him. The nicest ground he had was at Ascot and he was only beaten a length by Dawn Approach."