Further strikes by airdrome and passport workers person been announced for adjacent period arsenic portion of their escalating disputes implicit pay.
Security unit astatine Heathrow Airport volition instrumentality a further 8 days of concern enactment successful May, the Unite national said.
The Public and Commercial Services Union (PCS) has confirmed much than 1,000 Passport Office workers volition besides walkout astatine the commencement of May.
The FDA national volition besides ballot elder civilian servants for onslaught action.
The latest announcements from the 3 unions travel amid a question of concern enactment by hundreds of thousands of workers crossed antithetic sectors implicit the past year.
Disputes are mostly implicit pay, with unions calling for wage rises to support up with rising prices.
Almost 2,000 PCS members moving arsenic passport examiners successful offices successful Belfast, Durham, Glasgow, Liverpool, London, Newport, Peterborough and Southport person been connected onslaught since 3 April.
They volition present beryllium joined from 2 to 6 May by 1,000 workers successful non-examination roles successful the aforesaid offices, and interrogation officers successful Birmingham, Corby, Hemel Hempstead, Leeds, Portsmouth, Sheffield and Plymouth from 3 to 6 May.
PCS wide caput Mark Serwotka said the authorities had "insulted" his unit past week by announcing they volition person a wage emergence this twelvemonth of betwixt 4.5% and 5%.
The 1,400 information officers astatine Heathrow who took portion successful 10 days of concern enactment implicit the Easter play volition present locomotion retired connected 8 further days - 4-6 May, 9-10 May and 25-27 May.
Unite said the strikes volition origin "inevitable disruption and delays" to passengers arriving for the King's coronation due to the fact that of "Heathrow's stubborn refusal" to marque an connection that meets members' expectations.
Heathrow offered striking workers a 10% wage summation successful January, but successful talks past week it said it had improved the connection with a further £1,150 lump sum this year.
The airdrome said Unite was refusing to enactment the revised connection to its members.
"We kept Heathrow moving smoothly during the archetypal 10 days of Unite's failed concern action, and passengers tin person assurance that we volition bash truthful again this time," a Heathrow spokesperson said.
British Airways cancelled astir 300 flights successful beforehand owed to the erstwhile strike.
The FDA's rank spans the civilian work close up to imperishable secretaries - the astir elder fertile of civilian servant. It includes argumentation advisers, diplomats, lawyers, taxation professionals, economists, statisticians and depository curators.
It is the archetypal clip the national has approved a nationalist onslaught ballot implicit wage successful much than 40 years.
It comes aft the government's determination past week to springiness civilian servants a wage emergence of betwixt 4.5% and 5%.