Brighton: London's horror spate of terror attacks could have been much worse, mayor Sadiq Khan has said, revealing that police have foiled seven terror attacks in the British capital since March.

Mr Khan said the seven plots were in addition to the attacks at Westminster, Borough Market, Finsbury Park and Parsons Green that killed a total of 13 people, including two Australian women, Sara Zelenak and Kirsty Boden.

London Mayor Sadiq Khan has renewed his call for more police resources in the British capital. Credit:Latika Bourke

"Between March this year and now, there have been four attacks but seven [more] have been thwarted," he said at an event on the sidelines of the Labour Party conference in Brighton.

In July, the commissioner of the Metropolitan Police said authorities had foiled six plots in the four previous months.