Engineers from Scotland Gas Networks (SGN) will begin six months of works to replace ageing pipes in the north west of the city at the start of June. Large sections of the main arterial route along Queensferry Road and Hillhouse Road will be included and the works there will run for 12 weeks. Iron pipes within 30 metres of residential properties must be replaced with new polyethylene pipes, according to Ofgem. Local diversions will be in place while the £1 million project is carried out. Work is due to start on side streets on June 4 and work on Queensferry Road is scheduled to begin on July 2. SGN said it had chosen the quieter summer months to minimise disruption. The taxi trade has warned that although the schools will be closed, the route will be packed with buses destined for the Festival and Tattoo. Raymond Davidson, secretary of the Edinburgh Taxi Association, also urged transport chiefs to avoid works around the Royal Highland Show on June 21-24 . He said “There is no doubt there will be huge disruption. Although the schools are on holiday it’s a very busy time. “Queensferry Road is also one of the main routes to Fife and there are thousands of drivers commuting every day. It’ll be a nightmare.” He added: “I realise these works have to be done but those behind the project really need to make sure there’s proper signage up so drivers know what to expect.” SGN’s managing director, John Lobban, said: “Work will be carried out during the quieter summer months and during the trades holiday fortnight to minimise disruption. “It’s our responsibility to ensure a safe and reliable gas network. We appreciate that our works do sometimes cause disturbance, that is why we have been working closely with the city council on the planning of these works.” Euan Kennedy, road services manager at the council, said: “Work is due to begin on the major route, Hillhouse Road, on July 2 to coincide with the start of the trade and school holidays when traffic will be quietest. “This has been considered and agreed by the city-wide transport management group and has also been the subject of consultation with Lothian Buses and Lothian and Borders Police, both of whom agree that this is the best time to carry out these essential works.”