I came up behind a pair of drab Vauxahll Senators, overtook the first one almost immediately and then when the road opened up again I pulled out to overtake the second... Only to find the driver was accelerating hard. Some old Vauxhall - even a 3.0 six cylinder one - is no match for a mighty ZX10 and I pulled past him easily and disappeared off up the road.
The two cars stuck behind me like glue and I eventually decided letting them passed would be the wise thing to do. Very wise, as it turned out; each car had four burly blokes with neat haircuts crammed in it, and as they passed me the passenger of the second car made a pointy-gun sign with his fingers, to the amusement of his colleagues.
It wasn't until I was telling this tale to a friend who had recently completed a pursuit driving course for HM Customs in the area that he explained what had probably been going on.