The Sydenham Bypass, partly based on the autobahns of the 1930s, opened 50 years ago today, as the first dual carriageway in Northern Ireland.

Although only a short stretch of road – less than three miles long – it was pioneering for its age, built to near-motorway standard and unveiled weeks after England's M1 opened to a fanfare.

But the Sydenham Bypass would have beaten the M1 to opening by almost two decades, had it not been for the outbreak of the Second World War in 1939, which caused work on the route to cease.

This was an ironic twist, because the road's Scottish engineer R Dundas Duncan had visited Germany two years earlier as part of a British delegation to inspect Adolf Hitler's much-admired new autobahns, which revolutionised long distance motoring.

Construction began the following year, before being interrupted the year after with the outbreak of hostilities. Then, following the war, there was insufficient money to finish the project until well into the 1950s.

Finally, at its opening on November 23, 1959, those who ruled Northern Ireland, from the Prime Minister Lord Brookeborough down, turned up to bask in the breakthrough - decades after congestion had first been seen on the now bypassed Newtownards Road.

The News Letter reported: "The opening of the road, which has special paths for cyclists, was as the Governor (Lord Wakehurst) described it, a new era in road development."

Covered stands were erected for the ceremony, the paper reported, and dignitaries then drove to Stormont where "the Government gave a luncheon".

The road is now one of the busiest in the Province and plans to widen it to three lanes are in the early stages.

Road enthusiast Wesley Johnston, who runs a popular website, has been researching the bypass ahead of the anniversary.

He said: "Although most who use it every day do not realise its significance, the Sydenham Bypass is remarkable in being the first, modern dual-carriageway constructed in Northern Ireland."

The bypass was due to form part of an M3 motorway to Bangor which, like most planned motorways in Northern Ireland, was never built.

A bridge over the Lagan, completed in 1995, was the only section of the M3 that did get constructed.

The first motorway in Ulster, the M1 to Lisburn, opened two-and-a-half years later in mid-1962.

The Sydenham Bypass was improved in 1966 with the new Bridge End Flyover and Queen Elizabeth Bridge.

Mr Johnston said: "The Sydenham Bypass now carries almost 60,000 vehicles per day, and has stood the test of time remarkably well."

n Wesley Johnston's roads website is at http://www.wesleyjohnston.com /roads/