Dublin's infamous gridlock is an example of how a city's evolution can drive it into a dead end that threatens its very life. Can the capital continue to add new cars and not eventually remove many of the reasons why a person might choose to live there?

Yet these crises are a regular part of the ongoing life of big cities everywhere, according to Mr Gordon Masterton, a director in the Babtie Group, an independent technical and management consultancy. Mr Masterton addressed the issue of "sustainable cities" during a recent presentation to the British Association in Glasgow.

"It is the robust expression of the human spirit in its buildings and its cities and all they contain, which captures the true essence of civilisation, good or bad," Mr Masterton argues. "Sustainability is therefore dependent on a wish to sustain."

Cities can reach a crisis point and then either pull through and continue to thrive, or falter and go into decline. London was at such a juncture 150 years ago, he said. Six million people visited the Crystal Palace and marvelled at the achievements of Britain's industrial and economic power in the Great Exhibition of 1851.

"But away from Hyde Park, visitors would have seen a metropolis struggling to cope with the influx of rural workers."

Transport, water supplies, street cleaning, housebuilding were all inadequate to deal with London's growing population.

The "issue of drainage was a national scandal" as proven in 1849, when a cholera epidemic killed 14,000 people. "But still, it took until 1858, 'The summer of the great stink' to bring matters to a head," he said. The smell smothering the city was so bad that MPs fainted in the House of Commons.

Money was found and a civil engineer, Joseph Bazalgette, designed a scheme of 83 miles of intercepting sewers. The system was opened in 1865 before a collection of grandees that included the mayors of London and Dublin, the Prince of Wales and several archbishops. The "disease-ridden, congested metropolis" was transformed, Mr Masterton said.

"Today we could say that London in the 1850s was not sustainable." But through improvements in the civil engineering infrastructure, the city flourished and survived.

"Without this intervention, London would have decayed into a putrid backwater and the great step-change of urbanisation may well have languished as a failed social experiment."

This same type of "quantum jump" in the quality of life can also be seen in the introduction of the motor car. "Without the quantum jump intervention of the motor car, we would be relying on horse-drawn vehicles for secondary transport links to supplement the rail network," he argues.

The long term sustainability of the modern urban lifestyle has been questioned for many years, he said. The "Limits to Growth" report on sustainability of cities published in 1972 provided a pessimistic outlook. It predicted the collapse of civilised life on earth around the middle of the 21st century.

The updated report "Beyond the Limits of Growth", published in 1992, was no less sombre, Mr Masterton said. "Other future forecasters have taken a more optimistic view and believe that when the need arises, new technologies will be developed."

Technology, for example, is being used here to bring the former Dublin Gas site back to life as a living community and place of work.

The toxic soils are being removed and an ambitious development plan - detailed above - has been published.

Yet will the city survive the pressures being placed on it by a lack of an effective and efficient mass transit system in favour of an overburdened and limited road network? There are pessimists who would say no. Yet Mr Masterson is amongst the optimists for the survival of the urban context. "My view on the sustainability of cities is one of cautious optimism," he says. London was an example of a city brought back from the brink in 1858.

With the steady inputs of investment and skilled asset management, coupled with the vigour and vitality of politicians and engineers to identify better solutions, with the courage to take bold steps on a grand scale when necessary, the city as the hub in the wheel of our civilisation has a long future, he believes.