Harrow could be facing a measles epidemic - with more than four times as many cases of the disease as two years ago.
Since April this year there have been 17 suspected cases of measles in the borough - compared with four in the whole 2005/06 financial year.
The next two fiscal years saw the rates stay at 14 cases each.
But with only four and a half months gone in this term it is anticipated the numbers will increase substantially.
Figures show Harrow's vaccination rate is just below the national average at 84 per cent - just four per cent away from the level at which an epidemic is a real possibility.
MMR (measles, mumps and rubella) inoculation levels nosedived after medical studies in the 1990s suggested there was a link between the vaccine and autism.
But doctors have since refuted the claims and are urging parents to immunise their children.
Martin Rhodes, a borough GP for 30 years, is medical director of Harrow Primary Care Trust.
He told the Observer today's parents had not seen the horrors the disease is capable of: "Sooner or later a child is going to die from it. And for every child that does there will be another left with chronic lung disease or brain swelling. And it is completely and utterly preventable.
"Parents now in their 20s and 30s never saw the effects of it before there was a vaccine.
"They think it's something like chick-enpox that you have to go through. It's not the same thing at all."
He said he had seen people left disabled by the disease over his decades of service.
One patient was left deaf and another had part of their lung destroyed.
Although there have been no deaths in Harrow so far from measles, he feared if the current trend continued it would be 'inevitable'.
Addressing the fears some parents still had over the MMR vaccine he said: "I'm afraid there are some people in our profession who have put doubts in people's minds. We are the only country where this has been a problem."
Steve Baker, a 34-year-old father-oftwo, took the decision to immunise his daughters, one-year-old Poppy and Daisy, six.
He said: "There is no evidence to link MMR with autism, but even if one in every 100,000 kids vaccinated did show symptoms of it you are still risking their lives by refusing the jab.
"Because it has not been proven it seems a very dangerous risk to take."
Harrow PCT could receive £60,000 from the Department of Health to tackle the problem.