Look right!
What it really means
Because British traffic drives on the left, cars come from your RIGHT first when you cross. Many London roads have "LOOK RIGHT" or "LOOK LEFT" painted on the ground — trust the paint, and look both ways anyway.
Context, tips & common mistakes
Traffic on the left means every crossing instinct from a right-hand-traffic country is reversed: the nearest lane comes from your right, which is why London paints LOOK RIGHT on the tarmac at crossings. Trust the paint, and look both ways anyway — one-way streets, cycle lanes and quiet electric cars all defeat assumptions, and cyclists may legally come from unexpected directions.
At zebra crossings (black-and-white stripes, flashing amber beacons) traffic must give way to pedestrians, but establish that a car is actually stopping before stepping out — especially your first months here, while your instincts recalibrate. Pedestrian light buttons at pelican crossings do need pressing, and jaywalking is not an offence in Great Britain: crossing elsewhere is legal, merely at your own judgement.