A couple of years ago, it looked as though American consultants and project managers were invading Britain. Giants like Bechtel, Parsons Brinckerhoff and Fluor Daniel had moved across the Atlantic to programme manage Railtrack's major civil engineering projects.
San Francisco-based Bechtel was becoming established having rescued major projects like the Channel Tunnel and the Jubilee Line Extension while also developing a strong presence in the water sector. Others, like Parsons Brinckerhoff and URS, had also bought British consultants.
But it is not all one way traffic.
British consultants, and British engineers have been quietly establishing their own Stateside presence for decades.
Firms like Mott MacDonald and Arup set up their US businesses many years ago and a spate of recent takeovers has taken firms like WSP and WS Atkins across the Atlantic too. Mott MacDonald and Arup have since strengthened their presence in the booming £641bn US construction market through a combination of local acquisitions and organic growth.
At the same time, Maunsell's new US parent Aecom has started using the consultant's British engineers to boost its own capabilities in bridge building and tunnelling - one of the main reasons behind Maunsell's recent recruitment of Hyder Consulting's bridges team (NCE Arup and Mott MacDonald also have some British engineers working in their American offices. There are signs that WSP will start to send staff out to its New York-based structures subsidiary Cantor Seinuk and WS Atkins is also expected to swap UK engineers with their colleagues in Oklahoma.
To an extent British engineers are an extra resource in a booming construction market, already short of well qualified technical staff. Cantor Seinuk, for example, is struggling to find Americans to cover its workload and has already started sending work across the Atlantic to London.
Pressure on resources has also forced major public sector bodies like California's transportation department Caltrans to contract out design work. This was traditionally done in house so has now created opportunities for consultants like Mott MacDonald, and Maunsell via its Aecom sister firm DMJM Harris.
Caltrans has even agreed to pay to relocate foreign engineers to California to fill the skills gap.
Much of the pressure on resources has arisen from America's vast £125bn Transport Equity Act (TEA21) spending programme. More money is also being pumped into the nation's airports under the US government's £29bn Airport Investment & Reform Act programme.
The TEA21 money mainly targets repairs to the nation's crumbling and neglected roads and bridges. Most of America's major long span bridges were built more than 30 years ago, with many like San Francisco's Oakland Bay Bridge built in the early part of last century. They have been largely neglected since.
But it is not just about UK staff making up the numbers - it is skills that are sought.
Few major new bridges have been built in the US since the early 1970s. The American engineers have missed out on a generation of expertise.
In the meantime, engineers working for Mott MacDonald and Maunsell have built up experience at home, on projects like the Second Severn and Dartford crossings, and abroad on the Tsing Ma and Kap Shui Mun bridges in Hong Kong.
Maunsell's current bridges team also includes engineers who were involved in the strengthening of the Tamar suspension bridge in Devon and the Avonmouth bridge near Bristol.
Mott MacDonald's US joint venture Hatch Mott MacDonald has so far used its experience to secure a role in the team recently chosen as preferred bidder for the repair, maintenance and reconstruction of San Francisco's 13.4km Oakland Bay Bridge.
'We will provide all the construction support services, ' says Hatch Mott MacDonald central west region area manager Cara Strom. 'Caltrans does a lot itself, but can't staff something of this magnitude with such unique engineering demands.'
British tunnelling engineers are also finding themselves in demand in the US. Over the last 10 years they have become adept at soft ground tunnelling on projects like Heathrow Express and the Jubilee Line Extension.
Since the US has built relatively few complex soft ground tunnels it is turning to engineers at Maunsell and Mott MacDonald to help out.
At the same time, there has been a spate of tunnelling projects, creating a shortage of local American engineers. Mott MacDonald divisional director John Moss is working for a Bechtel/URS/Greiner joint venture which is designing a series of tunnels to take a section of the new £3.1bn extension of the Long Island Railroad from Queens under the Hudson river into Manhattan.
His curriculum vitae covers projects ranging from the Los Angeles Metro and Boston Harbour clean up to the Jubilee Line Extension and Channel Tunnel.
As design area manager for the Queens tunnels, Moss finds the project draws on his experience in soft ground tunnelling on the section of the new line built under railway sidings east of the Hudson. But his expertise in hard rock tunnelling will also be vital as the line moves under Manhattan's skyscrapers.
Sitting in the project office high above New York's bustling 7th Avenue, Moss says that American consultants are increasingly keen to use British expertise to strengthen already strong teams, when bidding for major projects. Consultants often team up to offer a depth of individual expertise.
'You have to have the best team, and you have to make your team look so overwhelmingly strong that you can't lose the job, ' he says.
Doyle Wiste, senior vice president at Maunsell sister company DMJM Harris also confirmed that it was seeking UK engineering expertise to boost skills on a 2km bored tunnel in Colorado.
'We brought four British people into the Colorado office because of their depth of tunnelling experience, ' he says, adding that the DMJM Harris team had more experience in cut and cover work than in bored tunnels.
Maunsell is also touting its bridge expertise in the US via DMJM Harris. It recently used this team in a bid for an on-call design, maintenance, inspection and refurbishment contract for Caltrans in the Bay area of San Francisco.
Although this bid was unsuccessful, the British/American team expects to pick up other contracts as it beds down.