The fire brigade have issued a level 2 response to the blaze which currently has six fire engines in attendance, more than were at the Lido fire in Troon in February.
Over 30 fire fighters are battling the blaze after the alarm was raised at 12.12pm this afternoon, Wednesday, April 18. Fire fighters were confronted by a serious blaze when they arrived on scene and additional fire engines and an Aerial Rescue Pump were requested.
Crews soon learned that no-one was in the building and attacked the fire with main jets and ground-based water monitors.
Homes close to the affected building have been evacuated as a precaution, and there are no reports of any injuries.
A spokesman for the fire brigade said: "A section of the thatched roof has collapsed, and firefighting operations are currently ongoing."
Police have confirmed that because of the fire the A77 through Kirkoswald, between Blawearie Road and Balvaird Road, has been closed in both directions to allow fire fighters access to the building which sits directly on the A77.
Motorists are asked to follow the signposted emergency diversion routes which are:
Southbound: Leave the A77 at Hogg's Corner in Minishant; follow the B7045, (signposted Crosshill) then take the B741 (signposted Dailly); continue on the B741 to Dailly, before joining the C30 (signposted Old Dailly and Girvan); stay on the C30, which connects to the B734 bringing you back onto the A77 at Girvan.
Northbound: Leave the A77 at Turnberry and join the A719; follow the A719 (Signposted Dunure) to Doonfoot; at Doonfoot, turn right (signposted Alloway) onto Greenfield Avenue and follow this to Alloway; turn left at Alloway on to the B7024 and then almost immediately turn right onto Doonholm Road; follow Doonholm Road until it connects back onto the A77.
Souter Johnnie's is owned and operated by Costley & Costley.