Aidan O'Brien has declared Sword Fighter and Housesofparliament alongside favourite Idaho for the Ladbrokes St Leger.

O'Brien, who has taken the St Leger four times previously with Milan (2001), Brian Boru (2003), Scorpion (2005) and Leading Light (2013), has an undoubtedly strong hand in the nine-runner contest.

Idaho has been the long-time ante-post favourite and heads the market at 8/11, having been placed in the Investec Derby and Dubai Duty Free-sponsored Irish Derby before pouncing from off the pace to land the Betway Great Voltigeur Stakes at York last month at the main expense of Housesofparliament.

Sword Fighter won the Queen's Vase at Royal Ascot and the Curragh Cup before being unable to land a blow at Goodwood.

John Gosden has also enjoyed four St Leger victories - with Shantou (1996), Lucarno (2007), Arctic Cosmos (2010) and Masked Marvel in 2011 - and will attempt to add to that sequence with Muntahaa, who made all in a handicap at Chester on his latest start off a mark of 108, having previously been a staying-on third in the King Edward VII Stakes at Royal Ascot.

Stobart Champion Champion Jockey Silvestre De Sousa partners Ventura Storm, who gave weight and a beating to Ormito in a Listed race at Hamilton on his penultimate start before scooping a Group Three prize at Deauville last time.

The field is completed by Harrison, well adrift of Idaho in the Great Voltigeur, and The Tartan Spartan, sixth to Sword Fighter in the Queen's Vase.

The nine horses declared are: Harbour Law, Harrison, Housesofparliament, Idaho, Muntahaa, Ormito, Sword Fighter, The Tartan Spartan and Ventura Storm.