Organisers GMB hope the strike will have the "maximum effect" on employer OCS as standards at public parks will visibly decline if maintenance work halts.
In May 2014 OCS won a seven-year contract covering all landscape maintenance operations at Hyde Park, Kensington Gardens, St James's Park, The Green Park, Grosvenor Square and Brompton Cemetery in London. It includes all horticulture work, litter picking, refuse collection, road/path sweeping, playground inspection, and grave digging at Brompton Cemetery.
Staff belonging to the GMB union were balloted for strike action after OCS served them notice to move from weekly to monthly pay. GMB regional officer Gary Carter said OCS planned to withhold two weeks' pay that members had already earned, and would give it back when they leave. The union added: "OCS will offer the two weeks as a loan that they will deduct over 12 months, putting the employees into debt and wiping out any pay award."
Carter said the state opening of Parliament, Trooping the Colour at St James's Park and Downing St gardens would all be affected. Royal Parks and OCS declined to comment.