The House of Lords has been warned it could be abolished if it tries to block Brexit later this month after a key bill cleared the House of Commons Wednesday evening.

The government saw off attempts by Remain-supporting MPs to frustrate Britain’s exit from the European Union, with the Commons finally passing the European Union (Notification of Withdrawal) Bill unamended, by 494 votes to 122.

Now the House of Lords will have to debate and approve the bill before Theresa May can formally give notice to the EU of Britain’s intention to withdraw under Article 50 of the Lisbon Treaty.

However, the government does not hold a majority in the upper chamber, with many peers passionately pro-EU.

Various outlets report a government source warning Wednesday night that the House of Lords will face calls for its abolition if it tries to scupper Brexit.

The BBC quotes the source as saying: “If the Lords don’t want to face an overwhelming public call to be abolished they must get on and protect democracy and pass this bill.”

Brexit Secretary David Davis has also called on the upper chamber to “do its job” and “do its patriotic duty and actually give us the right to go on and negotiate that new relationship”.

Before 1999, the House of Lords was primarily composed of hereditary peers who had inherited their seats from their ancestors. However, it is now largely made up of political appointees who hold their seats for life.

Many were appointed as loyalists to Prime Ministers Tony Blair, Gordon Brown, and David Cameron, and are largely pro-EU. By contrast, the remaining hereditary peers tend to be more Eurosceptic; however, they now form a small minority in the House.

The Liberal Democrats have already said their peers will table amendments to the bill. If the Lords approve any one of these, the bill will have to go back to the House of Commons for further debate, throwing the government’s Brexit timetable into chaos.