"Tube services are already being hit as a new phase of industrial action kicks in this morning with staff refusing to take out trains that have not been prepped in the previous 24 hours and also refusing to train up staff who have been shunted around the network, outside of their normal jobs and locations, to try and plug gaps created by the ongoing overtime ban," the union said in a press release.
Members of staff participating in the industrial action could potentially have to forgo pay for the entire shift according to the union, citing a letter sent to the workers by management.
The London Underground has recently been beset by numerous strikes, mostly related to concerns over workers' pay and conditions with the introduction of new 24-hour services.
On July 8-9, the UK capital's entire underground network came to a standstill due to a 24-hour strike, forcing millions of Londoners to use other modes of transportation.
