Here's a telling report in the Cambridge local press about the council trying to stop parking in cycle lanes.
Gilbert Road is a fairly wide 1930's residential street. Most of the houses have offstreet parking. So there's not much call for people to park on the road. In many cases, visitors could park in one of the side roads, or - now here's an idea - not come by car. The road has wide pavements with grass verges. If it's really, really necessary, a couple of parking bays could be cut into the verges. How many cases are there when someone absolutely has to visit by car and cannot park off the road? Not many I suspect. But still the residents regard on-road parking as their God-given right.
And that's the planning process in a nutshell. A relatively small group of people can frustrate improvements necessary for road safety. Because after all, the convenience of the few is more important than the safety of the many. Bear in mind that Cambridge has a relatively high modal share for cycling, so if it's not possible to put safe cycle lanes in Cambridge, it sure as heck won't be possible in Merton.
Any government that's serious about cycling needs to change the planning process so that there is a general presumption in favour of safe cycling. Of course we still need democratic accountability, but right now cyclists don't have any democratic rights in terms of the planning process. Every time, the wishes of small local interest groups overwhelm the interest of the large number of people who would like to cycle safely.