Castletown is host to the Isle of Man's other active road racing circuit, with events held continuously since 1955. Today the Billown Circuit is used several times a year and event includes events as part of the famous TT for sidecars and lightweight classes, alongside its own famed Southern 100 at the end of the summer.
Unlike the Mountain Course, Billown is a (relatively) short blast on roads to the north of Castletown, stretching for 4.25 miles and featuring a mix of high speed straights, tricky corner sequences and hairpin bends. From the start it heads flat our to Ballakeighan, a sharp right-hander taken in first or second gear. A good exit is vital for the next long straight out into the country and leading to Iron Gate, a fearsome right hander. Riders tip the bike in at speed and hope to avoid scraping the wall which looms large at the exit.
Passing over the railway, the course then emerges at the Ballabeg hairpin, a deceptively tight and bumpy corner, which requires early braking to ensure the forks are settled before tipping in; many a rider has found themselves sliding off if they are too ambitious here. Another high speed run ensures through Ballawhetstone, Williams Corner and onto Billown Dip, before heavy braking brings the riders to the hairpin at Cross Fourways. Up next are the Church Bends – a natural chicane bordered on each side by stone walls – and then the run through the fast Stadium Bend and onto the final corner – another hairpin.
The inaugural race, staged on 14 July 1955, was also the first event organised on closed public roads by the Southern Motor-Cycle Club, who had previously held races on the disused Andreas Airfield. Following the closure of the former RAF airfield in 1954, a new venue was needed and further impetus was given by the success of racers George 'Sparrow' Costain and Derek Ennett at the 1954 Manx Grand Prix.
The proposal of a "South TT" using roads around the new Castletown A5 by-pass and the Billown Mansion was initially met with a lukewarm response from officialdom when an application for a grant of £500 for race expenditure was rejected by the Tynwald Race Committee in April 1955. Instead the funds were raised from local businesses, who enabled the installation of a public address system. The Southern 100 Road Race was go!
Despite initially being a club race, the '100' attracted the interests of the holidaying tourists as well as the racers and soon went from strength to strength, first as a regional race in 1956 and then a national event the following year. It was added as a British Championship round in 1969 and more recently it has joined the Irish roads championship and has European venue status.
From the earliest years Billown began attracting racers of a high calibre – no doubt helped by the island's strong road racing heritage. Bob McIntyre – the first man do a 100mph-plus lap on the Mountain Course at the TT – Phil Read, John Hartle, Charlie Williams and Tom Herron were all among the famous names to take in the Southern 100, while the winner of the 1955 250cc event, Dave Chadwick, had placed fifth in the Lightweight TT on the Clypse Course only a month before.
The 'King of Billown' title however belongs to the late Joey Dunlop, who amassed a total of 31 wins at the Southern '100' in 26 years and 41 overall at the Billown circuit. Understandably a firm favourite with the fans, after his death at a road race in Estonia in 2000 the Ballanorris section of the course became dubbed 'Joey's Gate' in tribute.
Besides the Southern 100, Billown has hosted two more meetings for many years – the Pre-TT Classic Races are held over three days at the start of TT practice week, with the Isle of Man Steam Packet National Road Races held on the Saturday after the Senior TT. This latter meeting has now effectively been incorporated fully into the TT, hosting 125cc and 250cc TT events plus a support race.
It may be much shorter than the more famous TT course, but Billown is still fast. Ray McCullough broke the 90mph average barrier in the 350cc race in 1975, while 'the ton' was achieved by Brian Reid on his RG500 Suzuki, during the 1983 1300cc race. Speeds have continued to rise and the current lap record of 114.245 mph was set by Guy Martin during the 2013 Southern 100 Races.