Australian consultants John Connell Group for the design and construction of the Melbourne Underground Rail Loop, opened in 1981. The alliance continued with bridge and tunnel works across Australia and Southeast Asia, culminating in the formation of a joint venture company (Mott Connell) in Hong Kong for the design of infrastructure in and around Chek Lap Kok airport, including the Lantau Link. As time went on, many of the assets built by the founders of the company began to show their age. The increase in traffic flow through the Queensway Tunnel meant that the ventilation system could no longer cope and additional ventilation tunnels were built under MHA's supervision in the early 1960s. In the 1980s the Blackwall northbound tunnel, which David Hay had worked on 90 years before, was refurbished by Murphy construction under the supervision of MHA. In 1979 they began economical and technical research on possibilities for the Medellín Metro. The firm stopped trading as Mott, Hay and Anderson in 1989 when it merged with Sir M MacDonald & Partners to form Mott MacDonald. The firm of Mott MacDonald has since expanded its field of operations far beyond traditional consulting engineering (for example, it currently runs the education department of the London Borough of Islington). Channel Tunnel Mott, Hay and Anderson were heavily involved in the design and construction of the Channel Tunnel between France and Great Britain. The firm were first involved in a proposal to build a tunnel between Britain and France in 1930, but this was unsuccessful. The design proposed in this feasibility study – twin running tunnels with a central service tunnel – was similar to the design eventually built. In 1957, the firm acted as adviser to the Banque de Paris et des Pays-Bas for another unsuccessful scheme. In the early 1970s, the firm capitalised on work funded by British Rail to develop means of calculating the aerodynamic behaviour of high-speed trains in long, complex tunnel systems (the resulting methods are still used today to design tunnels for rail traffic). MHA and French firm SETEC were appointed as joint advisers to the British and French Channel Tunnel Companies, who proposed a workable scheme. Exploratory construction contracts were let, but the British Government abandoned the scheme in 1975, with the first tunnel boring machine (built to dig the service tunnel) literally sitting on its launch frame. Despite the lack of funding, a short