Does the time difference between Lagos and London change during the year?

Yes. Because of daylight saving time the gap moves between 0 and +1h.

When is the best time to call London from Lagos?

Between 09:00 and 17:00 in Lagos, which is 09:00 to 17:00 in London.

Lagos and London are on the same local time. This gap is not fixed: daylight saving time moves it between 0 and +1h during the year.

Lagos

Nigeria

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London

United Kingdom

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A 9-to-5 day in each city overlaps for 8h. That is 09:00–17:00 in Lagos, which is 09:00–17:00 in London.

City	Time zone	UTC offset
Lagos · Nigeria	Africa/Lagos	UTC+1
London · United Kingdom	Europe/London	UTC+1

What is the time difference between Lagos and London?: Lagos and London are on the same local time. This gap is not fixed: daylight saving time moves it between 0 and +1h during the year.
Does the time difference between Lagos and London change during the year?: Yes. Because of daylight saving time the gap moves between 0 and +1h.
When is the best time to call London from Lagos?: Between 09:00 and 17:00 in Lagos, which is 09:00 to 17:00 in London.