Visa United Kingdom

No Visa required.

Already stated in the previous post, no visa required.

Though I wouldn't bother with websites that are not UK government sites -- https://www.gov.uk/uk-border-control

https://www.gov.uk/check-uk-visa

Also Airlines use the IATA database to confirm necessary documents that a passenger should have -- https://www.iatatravelcentre.com/

Do you have a US passport? The other answers are based on that. If you have a passport from another country that may be why the airline rep told you you need a visa.

Curiosity pushes me to ask …. Which airline?

yes, the answer depends on your passport, not the country you are travelling from.

Thank you. Yes, have passport.

Marilyn:

We meant: is your passport an American one?
If not, that might be why they said you need a visa.
Check here:

https://www.gov.uk/check-uk-visa

Thank you for your feedback and sharing links, very helpful. I do have USA passport.

Then no visa is needed.
In theory, to enter the UK, your passport only needs to be valid "for the duration of your stay", but since many countries require 6 months' validity from entry date, if yours is valid for less than that you could consider a replacement.

Airline staff are not always up to date on these matters. I had a checkin person with WestJet airlines in Calgary tell me I would have to go through customs there in Calgary for a Calgary to Heathrow London flight. She was incorrect. What she was probably thinking of was the US customs that have offices in Canadian airports for flights to the US. Maybe she just had a momentary lapse, or maybe she really didn't know. Either way, it's best to get info from official site and resources, not airline staff.

The airline staffer could have done a deeper check into the visa question from the OP.
Some travelers may not have access to a Forum like this and get anxious worrying about what might become a problem for them after being given misinformation.
Years ago, a travel agent in a big travel company here at the time literally argued with me that Glasgow was not in the UK , it was only a part of Scotland, therefore I was not entitled to a perk included in the flights I was booking.
Fortunately, I had lived in Scotland previously and got the perk.

"Years ago, a travel agent in a big travel company here at the time literally argued with me that Glasgow was not in the UK , it was only a part of Scotland, therefore I was not entitled to a perk included in the flights I was booking"

Oh my word....sounds like the people who think you need a passport to visit NEW Mexico...

I can understand Greg's issue with wrong info from the airline. But airline representatives should definitely know whether or not someone with a US passport needs a visa for somewhere as heavily traveled as the UK or EU.

Pam, Or my family member who commented on FB about someone in Hawaii being "out of the country".

A little unrelated location-wise, but I was booked to travel to Germany in Sept. 2021. The ticket agent refused to let me board because she thought there was a ban on US/Germany travel due to the pandemic—despite official German government web sites and friends in Germany stating otherwise. I waited until the flight departed, hoping they would figure it out in time. Went back the next day and was able to fly, but that one uninformed ticket agent cost me a chunk of my trip, some cash and almost cost me a pre-reserved ticket for a special art exhibit in Dresden (fortunately they let me in late).