Alternative routes include leaving academia at some point, before or after achieving a post-graduate qualification, and going to work for one of the major construction research institutions. Whichever route you take, getting funds for research will be one of your major preoccupations.
Most universities these days would advise their undergraduates to go for an MSc first if they see their future in research and/or academia. MScs were traditionally for graduates returning to academia after some years out in the profession, but these days fewer and fewer established professionals are prepared to face the inevitable drop in income involved.
Most of those who take this route will have financial backing from their employers, and will be undertaking research of direct and immediate benefit to the sponsoring organisation. And nearly all who obtain the qualification this way go straight back to their previous occupation. However, as part of the long-term convergence of academic standards across Europe, a MSc taken straight after graduation is becoming the preferred route to a PhD.
With the MSc under your belt the next step is to find a funded PhD place. The problem is that universities have very little in-house funding for such posts, so the cost of fees and any stipend paid to the research student have to come from the government research funding bodies, such as the Engineering & Physical Sciences Research Council, or from industry. Expect no more than £12,500 a year from such sources, even in London, and it could be much less. It will be tax free, however, you may be able to supplement this by contributing to consultancy work carried out by the department or by teaching undergraduates.
An alternative is an "engineering doctorate". These are four-year projects, during which you would be expected to spend most of your time on the premises of a sponsoring industrial organisation, such as a water company or a materials producer.