A Briton already serving a jail term in Kenya was charged on Wednesday with robbery with violence, a capital offence that carries a death sentence.

Briton Jermaine John Grant and others were accused of robbing four police officers of their loaded rifles at a police post in Wajir, near the border between Kenya and Somalia, in 2008, and escaping from police custody.

The charge sheet from the Chief Magistrate's Court said Grant used the aliases Ali Mohamed Ibrahim and Peter Joseph, and was arrested while clad in a black robe of the sort normally worn by Muslim women, a head scarf and a face-covering veil.

On Wednesday, Grant appeared in court handcuffed and wearing a red and black T-shirt and jeans.

Grant and his co-accused pleaded not guilty, and he looked calm as four witnesses testified against him.

The trial was adjourned to May.

Grant is currently serving a two-and-a-half year jail term, handed down in late December, for being in Kenya illegally. He has applied for his sentence to be reviewed by the High Court.

He is also charged with planning an attack in Kenya in late December after being found in possession of bomb-making material that included batteries, wire, ammonium nitrate, lead nitrate, acetone and hydrogen peroxide.

Kenya sent troops into neighbouring Somalia in October to pursue Islamist al Shabaab rebels, whom it blames for a string of kidnappings and cross-border attacks, often targeting tourists visiting Kenya.

It has stepped up security, both at the border and in Nairobi, as a result of the cross-border attacks, but its troops in southern Somalia are still subject to attacks by al Shabaab fighters.

(Reporting by Humphrey Malalo; Writing by James Macharia; Editing by Tim Pearce)