The A74 also known historically as the Glasgow to Carlisle Road, is a formerly major road in the United Kingdom, linking Glasgow in Scotland to Carlisle in the North West of England, passing through Clydesdale, Annandale and the Southern Uplands. A road in this area has existed since Roman Britain, and it was considered one of the most important roads in Scotland, being used as a regular mail service route. The road received a substantial upgrade in the early 19th century under the direction of Thomas Telford, who made significant engineering improvements, including a new route over the Beattock Summit and the Metal Bridge just in England just south of the border. Engineering improvements continued throughout the century and into the 20th, and it became one of the first trunk roads in Britain in 1936. From the 1960s the road started to be replaced by a parallel motorway, largely designated the M74. The last remaining section of all-purpose road on Telford's original alignment, the so-called "Cumberland Gap" between Carlisle and Metal Bridge, was replaced by a motorway in 2008 after years of delays due to a breakdown in discussions between the Westminster and Scottish governments. Currently the A74 is a suburban route of local importance that links the Gorbals and Broomhouse districts of Glasgow, via neighbourhoods in the city's East End. The road was infamous for its allegedly high accident rate, being dubbed a "killer road", which exacerbated the need to provide an alternative motorway route. Several high-profile accidents occurred, most notoriously the debris of Pan Am Flight 103 in December 1988, which partially fell on the road near Lockerbie and caused several fatalities. Route Original route The original route as classified by the Ministry of Transport was published as "Carlisle (Kingstown)–Gretna Green–Lockerbie–Crawford–Hamilton–Cambuslang–Glasgow". It started at the junction of Parkhouse Road and Kingstown Road to the north of Carlisle city centre, and followed a northwest route, crossing the River Esk at Metal Bridge and the Caledonian Railway at the Mossband Viaduct before crossing the Scottish border at the River Sark. After passing through Gretna and Gretna Green, it followed the general line of the Caledonian railway toward Lockerbie and crossed the River Annan over a bridge at Johnstonebridge. It followed the Annan valley into a rural area away from any settlements as it crossed the Beattock Summit between the Annan and Clyde valleys towards Elvanfoot. This section is on a