Punters, jockey Johnny Murtagh and his boss Aidan O'Brien training out of Ballydoyle in Ireland, have done for Britain's top bookmaker in the last four months, latest figures show. Ladbrokes today revealed pre-tax profits fell 16% to £134 million in the first half as it took a caning at the hands of O'Brien at Royal Ascot.

The Irish trainer led four of his heavily backed horses into the winners' enclosure and had a staggering haul in the last four months of 17 winners in Group 1 races - the most prestigious in Britain, Ireland and France.

In July, the first trading month of the second half of its financial year, things had been going well until in the space of five days Duke of Marmalade, Henrythenavigator, and Yeats, all multiple winners this season for O'Brien, scored again. The extremely tight starting price odds on the winners at the Ascot King George meeting and at Goodwood indicate the weight of money that has poured on to O'Brien's horses.

"It has been moderately bloody and painful for us," said Ladbrokes chief executive Chris Bell.

"Ballydoyle are having a blazing season and good luck to them because their successes are good for racing and therefore in the long run good for us. The only good news for us is that the flat racing season is coming to an end."

Outside of the O'Brien effect and a poor euro 2008 where draws - generally good for bookmakers - were few, Bell said Ladbrokes is yet to feel effects of the economic downturn. Online betting and e-gaming revenues are up 18%, as is income from casino machines in its betting offices where it makes an average of £676 per machine a week.

"The figures show we have been pretty resilient, the sort of figures that anyone else on the High Street would give their eye teeth for," he said.

Ladbrokes is raising its interim divdend by 5% to 5.1p.