The hills are alive (or #janathon day 6)

London is, for the most part, flat. So flat, a flood barrier had to be built to prevent the city being deluged by high tides and wind-swept North Sea swell.
If you want to get lung-testing ascents and quad-punishing descents there are few better places in North London than Highgate and Hampstead Heath. Between the dog-clothing shops, swanky delis and yummy mummy cafes of Highgate and the viewpoint of Parliament Hill is probably the hilliest mile in London.
Today was traditional easy long-run territory. To bypass my natural instinct to try to turn all runs into tempo sessions, I took to the muddy paths, muffled the mile counts of my Garmin with headphones and picked the hilliest route I knew for a two-hour traipse. (Critically, this is the point of marathon training where the long runs are enjoyable without descending into repetition or freezing-cold tedium as the miles yawn out in front of you.)
Although overcast, with a fine gauze of drizzle hanging in the air, it was mild and still far drier than the past few weeks. The muddy paths had turned to a claggy clay-like mush, rather than pools of standing water. Hampstead was rammed with dog-walkers (and some pooches were kitted out in some very fine garb from the doggy couture shop up the hill), January joggers and at least one pair of pensioners parked on a park bench checking their iPad. (Hampstead is an alright area where house prices are best expressed in millions.)
Despite hills, mud and a determination to run slow, I found myself making fairly good progress and by the end of the run I’d overtaken numerous joggers, four cyclists, and covered 15.7 miles with more than 1100ft elevation gain in 1:57.