Hillingdon Lido

I don't know how I've missed a pool like this in the UK! Outdoor 50m, eight-lane lap swim pools are standard fare in Australia and other parts of the world where the year-round temperature warrants large outdoor swimming venues, but in the UK this is a rarity.

I'm also slightly surprised I've not been here before. Even more surprising is learning there is an indoor 50m pool here too. I need to check that my information sources are up to date!

I'm booked in for a swim at the new and much talked about Sea Lanes Canary Wharf this afternoon. I've paid and everything! But a meeting runs longer than expected and I don't fancy the 30-minute slog across London on the Tube in the heat, followed by a rush-hour escape from the city.

Instead, head to Hillingdon, conveniently located close to where the M25 meets the M40, also known as my route home.

The website recommends pre-booking because sessions can sell out during the summer. I'm sitting in the pool car park just after 2pm on a Thursday afternoon, though, and while the sun is out and blazing, how busy can it be?

Use the Better UK app to book a session. There are plenty of spaces, although at £11.50, or around $15.40, it isn't a cheap swim. These UK outdoor pools don't heat themselves!

Head in through the gates and there is no proper check-in, just a girl sitting on a plastic garden chair giving the booking email a quick glance before waving me through to the pool deck.

The sun is out, it is hot and the pool, all 50 metres of it, looks awesome.

Three lap swim lanes run down the left side, all fitted with proper wave-breaking lane ropes. A family splash session takes up the other five lanes. The pool sits beside what I assume is the main indoor pool hall and is surrounded by sun loungers and seating, plus a cafe hut selling coffee and ice cream. I don't see a single person visit it during the entire swim!

It is a lane pool with shallow wings on either side, making it a flexible pool for everyone. Best of all, on this sunny Thursday afternoon, it is very quiet. There is just one swimmer in each of the three lap lanes.

Head down the right side of the pool to the outdoor changing cubicles. A quick change, stretch and generous dose of sunscreen, then it is over to the lane side of the pool.

I've got the Shokz headphones on today and my phone is sitting inside the Yeti poolside dry bag. It will be interesting to see whether the Bluetooth signal stretches the full 50 metres. It works brilliantly in a 25m pool, at least while my head is above water.

Jump into the fast lane and make a start. We find out pretty quickly that iPhone to Shokz bluetooth range is about 40m! So after the connection drops on the first lap, I make a hasty fumble to press and hold both volume buttons at the same time mid-flip turn to switch to mp3 mode and dig into my backup soundtrack!

The water is perfectly cold and, to my surprise, very clear. It is hot and sunny today, which certainly helps. The sun stays out in force for the entire swim, except for the exact moment I finish, climb out and take the photo!

I'm after a slightly longer session today. The plan is a 3.2km plod, followed by another kilometre made up of 100s.

Wait for my lane buddy to reach the far wall before pushing off. After a few lengths, it becomes clear that we're both here for a long swim. We pass directly over the centre line on the pool floor at exactly the same time on every lap. Lap after lap!

After 15 minutes, the sheer synchronicity of our pace starts to feel slightly freaky. She must be thinking the same thing. On a couple of laps, I push on and gain a metre or so, only to find that she wins it back on the next one.

I noticed her jump in the lane just as I arrived, so she must have a good 800m on me by the time I get into the water. I'd estimate she works through about 2km before getting out. I'm here for a while longer, pushing on towards the 3.2km mark.

The pool sits just off the end of the runway at RAF Northolt, so the occasional plane takes off overhead as I swim. Most look like private jets, along with what I think are Atlas C.1 A400Ms.

As the swim nears its end, the public splash side of the pool and the surrounding deck definitely get busier. Oddly, I'm also becoming increasingly aware of more detritus and hair in the water.

There are plenty of leaves on the pool floor from the start, but I think the extra people in the water begin stirring up the grime sitting on the bottom.

Finish with 4.2km in total, then head to the poolside showers