MPs are returning to Westminster to pay tribute to Jo Cox who was killed as she prepared to hold a constituency surgery.
Commons Speaker John Bercow agreed to the recall of the House to allow members to commemorate a colleague described as "perfect" by her family. The Lords are also returning.
Parliament had been in recess to allow MPs to concentrate on campaigning in the final days running up to the European Union referendum on Thursday.
In a break with Commons tradition MPs from different parties may sit together, rather than dividing along party lines with Government supporters on one side of the House and the opposition on the other.
Labour MP Jason McCartney, who represents Colne Valley next to Mrs Cox's Batley and Spen constituency, has written to Mr Bercow urging him to allow the move as a mark of solidarity.
The Leader of the Commons Chris Graying has indicated he is sympathetic to the idea, saying it is an occasion where "people should do what they feel comfortable doing".
Labour leader Jeremy Corbyn, who requested the recall, said there would be further talks before the sitting.
Tributes in the House will be followed by a service of prayer and remembrance at St Margaret's Church - often referred to as the "parish church of the Commons".
The killing of the 41-year-old mother-of-two outside the public library in Birstall in her West Yorkshire constituency has prompted an out-pouring of public grief.
MPs have praised her passionate commitment to causes such as the plight of Syrian refugees and her ability to work with colleagues on all sides of the House.
Local people have paid tribute to her infectious enthusiasm and tireless efforts on behalf of her constituents.
A memorial fund to raise money for charities she supported has reached more than £800,000.
Prayers were said on Sunday for Mr Cox's husband and children at a service at St Peter's Church, less than half a mile from where she died.
The Rev Paul Knight told the congregation: "Her humanity was powerful and compelling and we would do well to recognise her as an amazing example - a 21st century Good Samaritan."
Mr Knight said: "Jo was someone who went out of her way to help others. I regret to say I didn't know what she was like as a girl but she grew into a fervent advocate for the poor and oppressed.
"And though she must have been angry at times about what she saw here and around the world - those places she visited and worked - she seemed to me, at least, to be one who could fight with a passion and a disarming smile."
Mr Knight also remembered the bravery of pensioner Bernard Kenny, 77, who remains in hospital after he was injured as he came to Mrs Cox's aid.
Thomas Mair, 52, from Birstall, appeared at Westminster Magistrates' Court on Saturday charged with murdering Mrs Cox, grievous bodily harm against Mr Kenny, possession of a firearm with intent to commit an indictable offence and possession of a knife.