Flights leaving Heathrow could be hit this week by walkouts as part of a planned three-day strike by up to 275 cargo handlers of the union Unite.
According to Lloyds Loading List, talks over pay rises have broken down between the cargo handlers and their employer Swiss Cargo Services, with workers due to strike on Wednesday morning.
This could be followed by a second planned strike on 4 July.
Unite regional officer Kevin Hall told the publication that the action could be 'severely disruptive' to passenger flights, as well as hitting imports and exports of perishable goods such as fruit and flowers.