LONDON (REUTERS) - Thousands of migrants staged a day of action across the UK on Monday (Feb 20), either walking out of work or taking part in events to highlight their contribution to the British economy.

Pro-migrant protester Matthias Feist said:"This idea that there is a finite labour market and if all the migrants went, those jobs would have gone to British people, just doesn't work."

Called "one day without us", it was their first day of action as Brexit looms large.

Britain's House of Lords began debating the Brexit bill which, if passed, will give the government the go-ahead to formally start talks on divorce proceedings with the European Union.

Lawmakers have already backed the proposed law authorising Prime Minister Theresa May to inform the EU of the UK's intention to leave.

But the leader has yet to end the uncertainty over whether the more than three million EU citizens living in the UK who were born elsewhere in Europe, are allowed to stay.

Ms Linda Larocca runs an Italian restaurant in central London. She decided to close this lunchtime bringing her staff, all from the continent, down to parliament.

"It is a general feeling that it is important to recognise, you know, the impact that the immigrants have got here in London, and generally everywhere. Italy has got a long history of immigration so we really felt it was important to be part of the day."

Also participating in the campaign are around 1,000 EU citizens, lobbying lawmakers for a guarantee that they can stay in the country post-Brexit.

While Ms Larocca's customers may have missed out on their Bolognese this lunchtime, organisers hope it sends a clear message about just how essential they are.