Two of Britain’s three biggest rail unions have announced walkouts for Oct. 1 in a move that adds to a number of strikes across various industries on the eve of the ruling Conservative Party’s annual conference.

The Aslef train drivers’ union and the National Union of Rail, Maritime and Transport Workers both said Tuesday that members will strike on a day when sorting staff and delivery workers at Royal Mail Plc and dockers in the ports of Felixstowe and Liverpool are already due to stage protests.

The Transport Salaried Staffs’ Association told Bloomberg News that it, too, is planning an announcement and didn’t rule out a strike on the same date, the Saturday immediately prior to the gathering of Conservative activists and Members of Parliament in Birmingham. 

The concurrent rail protests will make it tougher for members of Britain’s ruling party to get to their annual conference, while throwing down a challenge to new Prime Minister Liz Truss after her predecessor Boris Johnson said that disputes on Britain’s privatized railway were a matter for train companies and not the government. Aslef will stage a further walkout on Oct. 5, when Tories will be heading home from the conference.

The RMT said that Oct. 1 will be a focus for strikes across different industries as workers struggle to cope with the escalating cost of living.

“Transport workers are joining a wave of strike action, sending a clear message to the government and employers that working people will not accept continued attacks on pay and working conditions,” RMT General Secretary Mick Lynch said in a statement.

The RMT is among 11 trade unions to have begun legal proceedings against the UK government in an effort to block changes to labor laws. The application for a judicial review asserts that plans to allow agency workers to fill the roles of protesting staff would undermine their right to go on strike.

Read More: Ports and Trains Face New Wave of Strikes Once UK Mourning Ends

A previous round of planned action on the railway, which had included parallel walkouts by the RMT and Aslef, was put on hold following the death of Queen Elizabeth II.

The RMT’s 24-hour action will affect Network Rail Ltd. and 14 train operating companies, while there’ll be separate strikes by Arriva Rail London members, bus workers at FirstGroup Plc and on Hull Trains. Aslef’s walkouts concern 12 train operating companies.