Metropolitan Police civilian staff on New Year's Eve strike
Thousands of police civilian staff including 999 call handlers and detention officers are striking until midnight on New Year's Eve.
The Public and Commercial Services (PCS) union called the London strike in protest at a below-inflation 1% rise.
Scotland Yard said it had a continuity plan in place for the 24-hour strike.
It comes on the same day that FBU members of the London Fire Brigade will take part in a national strike over pensions and the retirement age.
The Fire Brigades Union members will stop work for six hours from 18:30 GMT. The government has criticised the action.
About 7,500 police and community support officers, detention officers in custody suites and administration staff started their strike at midnight.
PCS general secretary Mark Serwotka said: "The Metropolitan Police is not short of money. It does not need to force pay cuts on low-paid staff who help to keep London safe."
The force said New Year's Eve was one of the busiest days of the year for the service but it had "appropriate plans in place".
A Metropolitan Police spokesman said: "We have tried-and-tested business continuity plans for all eventualities, including industrial action.
"To ensure we are able to implement these plans, we stopped granting any further requests for annual leave or days off for officers and staff in a number of key areas for New Year's Eve in mid-December.
"In some cases we've also had to take the very difficult decision to cancel planned days off for officers with certain critical skills or in critical operational areas."