LONDON (Reuters) - Former trader Tom Hayes, who is facing criminal charges for the alleged manipulation of Libor interest rates, has changed law firms weeks before he is due back in a London court.

Hayes, a former trader at Citigroup <C.N> and UBS <UBSN.VX>, has switched to British law firm Garstangs Burrows Bussin from Fulcrum Chambers, Lydia Jonson, his former lawyer at Fulcrum, said in an email. Garstangs Burrows Bussin did not immediately respond to a request for comment.

Hayes, 33, is expected to indicate how he intends to plea to eight counts of conspiracy to defraud at the London court hearing, which is scheduled for October 21.

Hayes, who has also been charged by the U.S. Department for Justice, and two former RP Martin brokers are the first individuals to be brought to court over a scandal that has become a symbol for the financial industry's self-serving excesses.

Prosecutors allege Hayes manipulated Libor benchmark interest rates, which are used as a benchmark for more than $300 trillion of products from derivatives to home loans, with staff from 10 leading banks and brokers over four years.

To date, U.S. and British authorities have charged seven men in connection with Libor rigging, and Britain's Serious Fraud Office told Reuters last week it is poised to charge more.

As well as Hayes, U.S. prosecutors have charged Swiss-based former UBS trader Roger Darin and three former staff at interdealer broker ICAP <IAP.L>; New Zealand-based Darrell Read, his British-based supervisor Daniel Wilkinson and cash broker Colin Goodman.

(Reporting by Tommy Wilkes and Huw Jones, editing by Patrick Lannin)