A spokesperson said: “It is with regret we announce Patrick’s immediate resignation due to personal reasons. 

“We thank him for his service, which saw him help Alliance make an historic breakthrough in South Down at the Assembly, and wish him well in his future endeavours.”

Patrick Brown added: “I want to thank the people of South Down, whose support helped me and the local Alliance team substantially grow the party in the constituency.  

“It has been an honour to represent local people and help them on important issues. I am proud of my track record as a constituency MLA and remain committed to Alliance values, and look forward to seeing the party continue to grow across Northern Ireland. 

“This May, I will have been an elected representative for 10 years and feel the time is right to step aside for personal reasons. I am proud of the work I have done since being elected, including supporting those impacted by flooding, campaigning on environmental and animal welfare issues, and my work on the Windsor Framework and Infrastructure Committees.

"Alliance continues to have my support, as will whoever is co-opted by the party to fill the position of South Down MLA.”