Munt voted against the government and supported a rebel amendment demanding a moratorium on the use of fracking. Another 52 MPs joined Munt to stop the use of fracking.
The amendment was advanced during Monday's debate on the government's infrastructure bill but was defeated by over 300 MPs.
The government however did decide to acquiesce to 13 new conditions put forward by the Labour party that would need to be met before fracking can go-ahead.
The Environmental Audit Committee called for a halt to fracking because, in its view, the UK cannot develop a significant shale industry without breaching its carbon targets under the Climate Change Act.
Munt said in a statement:
It is with regret that I today handed in my resignation after 3 enjoyable years working closely alongside Vince Cable as his PPS in the Business Department.
I understood the implications of voting against the Government, but with my principles, in favour of a moratorium or ‘freeze’ on fracking, as endorsed by the Environmental Audit Committee’s Report published on Monday morning.
There was some confusion over whether Munt would resign earlier today after she said in a statement this afternoon:
Today, I have continued to pursue my duties as Vince Cable’s PPS, despite voting against the government and calling for a fracking freeze. I have attended two meetings this morning, and assisted three MPs (one government, two opposition) with matters concerning businesses in their constituencies.
As a parliamentary private secretary, Munt was bound by the principle of collective responsibility, and it would have been highly unusual if she had remained in her post.