Mask-wearing is to be optional for MPs but compulsory for parliamentary staff working in Westminster, new guidance has revealed.

New guidance emailed to MPs states that staff would be “required” to use face coverings until parliament heads for its summer break next week.

But the memo from Commons Speaker Sir Lindsay Hoyle, which has been leaked to HuffPost UK, states that MPs will only be “encouraged” to wear masks after the government lifts all Covid restrictions on July 19.

The email includes a range of measures to be adopted by parliament for the four days that parliament sits after so-called “Freedom Day” next Monday.

A section titled “Outside the Chamber” states: “Until 22 July, Members will be encouraged to continue wearing face coverings, and all others on the estate will be required to wear them while moving around the estate or entering venues.

“It will also mean that until the rise of the House the overall capacity of the estate will remain limited.”

One staff member working in the palace said: “It’s literally one rule for them…”

The general public will no longer be legally required to wear face coverings from July 19, although new guidance issued by the government advises that they should continue to be worn in crowded enclosed spaces.

But individual workplaces and individual transport bodies will be left to make their own decision to adopt face-masks as a requirement of entry or for staff.

The advice for inside the Commons chamber makes clear that from next Monday MPs will be able to sit normally once more, although they will be encouraged to wear masks when not speaking.

“Wearing face coverings will be encouraged for all those in the Chamber, although not mandatory,” it states.

“Ticks and crosses on benches will be removed – and prayer cards will be back in use…Barriers at the end of the aisles will be removed.”

The hybrid model of working, using remote video links as well as in-chamber speeches, will continue. Proxy voting will remain in place too.

“Perspex screens and stickers on the floors will remain until they can be removed over recess.”

A spokesperson for Speaker Hoyle told HuffPost UK: “We have no employment or contractual relationship with Members which would enable us to mandate the wearing of masks. We therefore encourage Members to support us in keeping the Estate safe.”

Garry Graham, deputy general secretary of Prospect, one of the trade unions that represents staff in parliament, hit out at the guidance.

“We urge the Commission to rethink this decision, and at the very least act to protect staff by issuing strict guidance that MPs must wear masks in the chamber and around the estate, both for safety and to set an example to the public about how to behave in crowded indoor spaces.

“It is frankly ridiculous that staff will be required to wear masks around the estate but the very MPs and government ministers who set the rules will not.”

He added it was “extraordinary” that the House of Commons Commission had decided to allow up to 650 MPs to crowd into the House of Commons from next Monday.

“With just a few days until the summer recess, there is absolutely no reason why this move could not have been delayed for a few months when the health situation would hopefully have improved and everyone would have had the opportunity to receive both doses of the vaccine.

“MPs may choose not to put themselves at risk in a full chamber, but staff are required to be there and their safety appears to be an afterthought once again.”

The letter from the Speaker, which says that the House of Commons Commission met on Monday and agreed the new rules, also says staff who work remotely will be encouraged to keep doing so until September when MPs return from their summer break.

“As we approach Step 4, the Commission recognises the strength of feeling and different views of everyone in our community,” the email said.

“The success of the vaccination programme gives us the opportunity to respond and manage the risk of Covid, in ways that allows us to return the proper functioning of the House.

“Levels of community transmission across the country, including in London, remain high, so we will maintain enhanced cleaning regimes across the estate and encourage Members to take personal responsibility for keeping themselves safe.

“The risk should however reduce further once everyone on the estate has been able to receive the full vaccination course.

“Until we reach this point at the start of September and while cases remain high, we will continue to take proportionate measures on the estate, including the use of face coverings.

“House staff and Members’ staff who are currently working remotely, will be encouraged to continue doing so until September.”