The 24-year-old, who lived in Chancton View Road with his family, before moving to Milton Keynes in 2015, had been at a British Lionhearts work event in the Houses of Parliament.
After leaving the main exit just after 2.30pm, it was just seconds later that he was forced to go back inside.
He said: “I can’t have taken more than a few steps outside when it all happened.
“I heard two or three really loud gunshots and saw some commotion with police, but I did not see the attack. I found myself caught up with complete strangers and we were all told to go back inside by officers.
“We then bumped into MP Andrew Percy, Minister for the Northern Powerhouse, up the stairs who let us into his office as we were in lockdown – none of us knew what was going on.”
Liam, who works as a reporter for insidethegames.biz, said he and around seven others had to sit in the office for four-and-a-half hours, but despite the horror, he said they all remained ‘calm’.
He said: “We all got on really well and we kept the spirit up in there. We felt safe and our thoughts were just with the families and police officers and people involved.
“None of us were involved and we didn’t do anything in particular, we just did what we were told. We weren’t the heroes, the police were.
“I cannot stress how great the police were in dealing with it all – they were superb. And the efforts from Foreign Office Minister Tobias Ellwood were truly heroic.
“At no point did I feel like I was in danger, the police and security forces dealt with it all so quickly.”
The previous Worthing College and Southampton University student said the ‘severity’ of the attack did not sink in until he was at home later that evening.
He said: “It was good to get home of course, what happened was a shock and it was a horrific incident and I think it will definitely alert some of the people in London.
“The biggest concern for me and for many I’m sure is just how close the guy was able to get to the Houses of Parliament.”
Don’t miss out on all the latest breaking news where you live.
Here are four ways you can be sure you’ll be amongst the first to know what’s going on.
1) Make our website your homepage
2) Like our Facebook page
3) Follow us on Twitter
4) Register with us by clicking on ‘sign in’ (top right corner). You can then receive our daily newsletter AND add your point of view to stories that you read here.
And do share with your family and friends - so they don’t miss out!
Always the first with your local news.
Be part of it.