A former senior British government official says Prime Minister Theresa May undermined her predecessor, David Cameron, in the run-up to Britain's June 23 referendum to leave the European Union.

The accusation is levied in Sunday's published serialization of a book by Cameron's communications director, Craig Oliver. Oliver writes that Cameron was driven to the edge of exasperation while seeking support from May for voters to keep Britain inside the EU.

May, home secretary in Cameron's government, was officially committed to retaining EU membership but maintained a low profile during the campaign.

In his book, "Unleashing Demons: The Inside Story of Brexit," Oliver says Cameron repeatedly pressed May to take a prominent role in pro-EU campaigning but she adopted a "submarine strategy of disappearing from view."

May declined to respond.