He, along with current Lib Dem leader Vince Cable, didn't show in Parliament missing the chance to embarrass the government on the Customs Bill vote which ended up passing by just three votes.
Farron was instead speaking at a Sherborne Abbey event at Digby Church Hall on the issue of faith and politics.
Issuing an apology on social media, he said: "I was authorised to be absent from the vote last night for a pre-arranged engagement.
"Nobody expected the vote to be as close as it was. We clearly called it wrong, as did Labour, and I take full responsibility for my part - the Tories don't deserve any luck."
Farron hit the headlines during the 2017 election as his Christian beliefs were consistently question by the media over the issue of sexuality.
Earlier this year, he told Premier he said things which he now regrets.