89% of members who voted in a ballot turned down the offer, with just over one in ten (11%) voting to accept it.

The unions submitted a joint pay claim in July. It outlined problems with starting salaries and the lack of progression from the bottom of the pay bands and spines.

The claim also highlighted that starting salaries for members in conservation do not comply with the Institute of Conservation’s recommended minimum salaries at entry level.

The union called on the museum to reopen discussions, which it has agreed to. But it went on to say it intended to impose the offer.

Prospect negotiator Brian Harris said: “Prospect will strongly object to the offer being imposed. We will make it clear that the 2019-20 pay discussions will only be concluded once a better offer is tabled and subsequently accepted by our members in a ballot.”

The offer included:

Pay bands:

• 5% increase to pay band minima
• 5% increase to pay band maxima
• all staff currently below the band maximum to receive an increase of up to 2.5% consolidated, capped for those reaching the band maximum
• any individual at, or approaching, the band maximum will have the balance of the 2.5% increase paid as a one-off non-consolidated amount
• all staff to receive salary and allowances equivalent to at least £10.55 an hour.

Pay spines:

• one progression increment for all staff currently below the spine maximum; this would represent a 2% step for most staff
• staff at the maximum on 31 March 2019, or reaching the maximum on 1 April 2019 with a less than 1.5% consolidated increase, would automatically move from the pay spines into the pay bands from 31 March 2019 and receive the relevant award under this heading
• all other staff within the pay spines would be offered a voluntary transfer into the pay bands at the same salary from 31 March 2019 and receive the relevant award offered to those within the pay bands
• all staff to receive salary and allowances equivalent to at least £10.55 an hour.