Provision for cycling in London remains "laughable", according to the Danish urban designer seen as the guru of liveable cities, arguing that the capital will be seen as an increasingly undesirable place to live unless it properly encourages pedestrians and cyclists.

Jan Gehl, an architect and planner who helped oversee New York's recent move towards widespread bike infrastructure, and has worked in a series of Australian cities, said London remained the preserve of young, gung ho cyclists, and he had never dared ride in the city.

"In Copenhagen I cycle with one grandchild at the front of the bike and another at the back, and a five-year-old grandchild on his own bike next to me. That can be done if you have bicycle lanes which are proper lanes which have kerbs and proper junctions. But in London, never," said Gehl, who is in the UK to give a talk to the Royal Institute for British Architects.

Gehl's comments come amid a major police operation in London in the wake of six cyclist deaths within a period of less than two weeks, which brought criticism of the cycling infrastructure introduced by London's mayor, Boris Johnson.

Johnson plans to introduce more segregated bike lanes, but the police crackdown has also seen officers advising cyclists to wear safety gear like high-visibility jackets.

Such an approach was antithetical to the sorts of measures which would bring in mass cycling, Gehl said: "It is my opinion that to have a substantive bicycle culture it is not only for the extreme sport enthusiasts, the freaks who think, 'It's a good day if I survive'. If, like in Copenhagen, you have a bicycle system that's a real system, it should be city-wide in the major streets. It should be like sidewalks – it goes from one entrance door to another entrance door."

Cities, he argued, should be designed so people feel "they are invited to walk as much as possible and to bicycle as much as possible", making cycling both normal and accessible to all ages.

London's bike lanes were far from this ideal, he said: "It's very problematic because you have the very narrow streets and very heavy traffic and very few provisions for bicycles. And where there are provisions, many times they are laughable. There's a 50cm-wide line with a bicycle symbol, which suddenly ends just when it gets dangerous. It's not serious."

Gehl, 77, criticised the idea of introducing an urban bike hire scheme, as in London, before the cycling infrastructure to make it safe. "This is a strategy of buying rental bikes, putting them all over a city, and saying to people, 'Fend for yourselves.' These rental bikers are not a critical mass so the car drivers are not used to there being cyclists, so they take a terrible risk."

One of Johnson's plans is for a pair of segregated cycle routes crossing London, north to south and east to west. Such routes could also be counterproductive, Gehl argued: "It's again something that's good for the freaks who like to go at high speed. It's not good in a city to do 40kmph on a bicycle. We should do 20kmph. The best way to get the 40kmph to slow down is to put a lot of grandmothers and children in the bicycle lanes. It slows down the whole thing and it gets more civilised."

These considerations were vital for the future of a city, he argued. "We have a new set of paradigms on where cities are competing. In the past they competed on who had the most parking spaces, or the biggest freeways, or the highest skyscrapers, but now there are many more questions about quality of life and liveability.

"It's interesting that of the three main lists of most liveable cities in the world, they have between 20 and 35 cities listed, and in none of them is any city from the UK. As far as I'm concerned that's because you have a very, very strong tradition of letting the traffic planners rule. They are still in a very strong position. They think that what you see out here is given by God. But in other cities like New York they've been very brave."

He added: "We are realising that if you have people walk and bicycle more, you have a more lively, more liveable, more attractive, more safe, more sustainable and more healthy city. And what are you waiting for?"