New Delhi, June 9 -- A US surveillance company that helps the American immigration service hunt people for deportation and supplies technology to the Israeli military is going to court for the right to help police London. Palantir said it will sue Mayor Sadiq Khan after he blocked a £50 million contract with the Metropolitan Police, turning a procurement dispute into a test of whether a city can refuse a firm on the grounds of what it does elsewhere.

the force had not put its strategy to the deputy mayor for policing and crime for approval as required, had not approached any rival supplier, and had left London at risk of being locked into a single company's technology with no demonstrated value for money.

Underneath the procedure w...