The Lib Dem leader looked deflated as MPs gave their final approval to a bill allowing Theresa May to begin official negotiations of Britain's divorce from the EU.
The staunch Remainer said the Commons vote had given the prime minister a “blank cheque” to “pursue a hard Brexit”.
Although MPs voted overwhelmingly in favour of the legislation, with 492 to 122 approving the European Union (Notification of Withdrawal) Bill, Mr Farron insisted the “fight wasn’t over”.
Tim Farron said Wednesday's vote was a
It is a very dark day that the House of Commons has given a blank cheque to a hard Brexit
Speaking on Sky News in a disheartened tone, he said: “In my mind, it is a very dark day that the House of Commons has given a blank cheque to a hard Brexit.
“This the moment that Theresa May has been given a blank cheque by both Conservative and Labour MPs to pursue a hard Brexit that was never on the ballot paper.
“What that means is the deal that Britain gets will be much worse than it would have been otherwise.
“The reality is you can’t have a strong NHS with a hard Brexit.”
Tim Farron said Theresa May would now pursue a "hard Brexit"
Earlier in the evening, Mr Farron’s desperate bid to secure a second referendum on Britain leaving the EU was crushed after only 33 MPs back his amendment.
He hoped to introduce the clause, which would have forced the prime minister to give the Commons a vote on her deal with Brussels once complete.
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The MP for Westmorland and Lonsdale slated Mrs May for now being in an “unbelievably weak” negotiating position by promising to remove Britain from the EU’s single market.
MPs voted overwhelmingly in favour of the Government on Wednesday
“She’s given away our strongest card, being in the single market is the fundamental success in our economy," he fumed.
“Being part of the biggest market in the world was not rejected in the June 23 vote and it wasn’t on the ballot paper.
“It seems to me that she now goes in there in a very weak position as her kind of supine trip to the United States proves.”
Despite imposing a three-line whip, Labour saw 52 MPs rebel against its leadership and vote against the bill.
Clive Lewis resigned from his shadow cabinet position minutes before the result was announced, claiming he could not vote for something which would hurt his constituents.
Labour's Clive Lewis resigned from the front bench
The shock resignation lauded the praise of fellow Remain politician, Mr Farron, who said it was a “noble” thing to do.
“There are many people on the Labour side today who will be written up kindly by history – sadly their leadership and many of their MPs won’t be,” he continued.
“I don’t know who is more to blame, the Tories for making this happen or Labour for letting this happen.
“But, I’m proud of every MP who decided to put the interests of this country first and the desire to protect the strongest possible outcome of this country.”