Tory MPs were left unable unable to get into the Houses of Parliament to participate in questions after being "trapped outside" by Insulate Britain protesters.
Commons Speaker Lindsay Hoyle criticised the situation as "totally unacceptable" and said it was "interfering with democracy" as he told MPs about the situation.
The Commons heard that Conservative MPs Darren Henry and Adam Afriyie were both unable to attend a session involving questions on transport due to protests outside Parliament on Thursday.
Afriyie was due to ask about re-evaluating the carbon cost of a third runway at Heathrow, while Henry was due to ask about encouraging the uptake of walking and cycling.
Hoyle told MPs: "We have got a slight problem. Darren Henry is trapped outside because Insulate Britain have blocked the access to the House.
"This is totally unacceptable. This is interfering with democracy. This is not what should happen and it is a tragedy that those constituents are not going to be represented by the member for Broxtowe."
He added: "Once again the Member of the Parliament can’t access the House to represent democracy and his constituents.
"Once again these people are blocking democracy and the fact that people are actually talking about the same issues and being blocked from doing so is totally counterproductive."
Around 50 Insulate Britain protesters glued their hands and feet to the floor as they sat in the street outside Parliament, while demonstrators also blocked two roads on Parliament Square.
Activists wearing orange high-vis jackets sat cross-legged in the road, while one man lay flat on the pavement.
One man was seen jumping on to a Met Police van holding an 'Insulate Britain' banner, while another reportedly glued his hand to a police van.
In a tweet the group wrote: "INSULATE BRITAIN AT WESTMINSTER. 62 people have blocked three roads around Parliament Square in Westminster this morning. 2 groups of people are sitting in the road with banners on Parliament square near the Peers’ entrance to the Houses of Parliament and on Bridge street."
Transport Secretary Grant Shapps said the Insulate Britain protesters were "preventing members from getting into the chamber which is completely unacceptable".
He said: "When it gets to the point that protesting against climate change prevents members from this House getting here to hold ministers to account and be heard it is clearly counter-productive.
"Contempt of court can lead to unlimited fines, and prison sentences. And we will be acting where the law has a gap in it through the Police and Crime Bill to resolve the gap that has led to this."
Watch: Who are 'Insulate Britain'?