Lancaster and Fleetwood MP 'nearly faints' due to health condition in 'ridiculous' 1km queue to vote in parliament
Cat Smith said MPs "shouldn't have been put in that situation", which saw some not observing social distancing rules and "whispering in each other's ears".
The Lancaster and Fleetwood MP has a health condition called Postural Tachycardia Syndrome (POTS), an abnormal increase in heart rate that occurs after sitting up or standing.
Symptoms include nausea, dizziness and fainting, and Ms Smith said the condition was triggered whilst she was standing in a 1km queue outside Parliament to cast her vote.
She has described the situation as "ridiculous", and said that MPs having to attend parliament during the coronavirus pandemic - rather than virtual voting from home - has left many communities without a voice as many MPs are shielding, and therefore cannot vote.
She also said she saw plenty of instances where MPs were not social distancing.
Last Tuesday, MPs backed a government motion to return to parliament after weeks of working remotely amid the COVID-19 lockdown.
The government's motion was adopted with 261 votes in favour and 163 against.
A cross-party amendment calling for remote voting to continue was also lost by 242 votes to 185.
Ms Smith said: "I've had the POTS diagnosis for about 10 years and I've managed it with medication, and by changing my diet, and making sure I don't get too tired.
"Generally most of the time you wouldn't notice anything different and you just learn to live with it and manage it.
"But we had this ridiculous voting system where we spent 90 minutes queuing to vote on how we vote in future.
"It was a very hot day, and many of us were out in the sun with no protection.
"It triggered my POTS and I knew I was about to faint, so I sat down on the ground knowing that if I didn't I would have hit the floor anyway.
"I've never let this condition stop me from doing my job properly.
"But this situation just wasn't right. I managed to cast my vote in the end, but so many of my colleagues weren't even able to be in Westminster, because they are shielding."
Ms Smith said that given how serious coronavirus is, she was shocked to see some MPs conducting themselves in a manner which ignored the government's own rules.
"I've seen MPs not observing social distancing, whispering in each other's ears, and it's so frustrating given how serious coronavirus is," she said.
"We shouldn't have been put in that situation, and it was wrong of Jacob Rees-Mogg to bring 650 MPs from every corner of the UK into one place.
"There were pinch points in the queue, and you couldn't progress without breaking the two metre guidance.
"Some MPs weren't even able to get in, and their votes were taken away from them, but more importantly, the community they represent didn't have a voice."
Ms Smith, who has a young son, said around 400 MPs attended the vote in the end.
"I've spoken to some MPs who said they're not coming back this week.
"They've given it a go, but they've made the decision to keep themselves and their communities safe.
"Jacob Rees-Mogg - the leader of the House of Commons, has already started to back down, and I'm hopeful that there will be changes made.
"Last month more than 600 MPs voted virtually, I voted on my computer.
"The virtual House of Commons system isn't perfect, and you lose the debating side of things, but there are so many empty seats anyway, and it's just putting people at further risk.
"It's about all the other House of Commons staff as well - thousands of people including door staff, police, cleaners, caterers, people having to travel on public transport - it's not fair on those individuals either."