Is it correct?

Tricolorrr533I've been to London last year.

It's wrong because the underlined elements don't go together.

It's wrong to specify a time (last year) in a clause with a present perfect tense (have been).

CJ

I've been searching for it around internet and there were a few controversies.. The explanation you've given me is the most common I've found, but yet, a British lady once told me it was correct.. go figure, these little rules always get me...

Thanks

Tricolorrr533a British lady

Just any old British lady? Or a British lady who is an expert in grammar?

It makes a big difference. Except for people who have some training in grammar, never trust a native speaker to answer grammar questions.

You can still say

I've been to London 3 times in the last year. (=this is ok because the 'in the last year' part denotes an unfinished period of time)

Perhaps, this is what the British lady had in mind.

By a British lady I meant an ordinary British lady, at least when I typed it.. hehe
But to be honest she is an English teacher here in Brazil.. no doubt that sometimes it isn't required for an English teacher to fully understand the language around here, let alone the fact that native English speakers are treated like gods at English schools in this country.

yeah, in the last year, I've seen that it makes it suitable on some website

Tricolorrr533native English speakers are treated like gods at English schools in this country.

How can I move there soon?

CJ, it's a mad house over there during the World Cup!

haha, I sure am interested in living in Cali, so if you find me a way of getting a Green Card.. Are you in need of Portuguese teachers in your area?

Tricolorrr533But to be honest she is an English teacher here

I have met some 'teachers' who have no training or qualifications at all. I have also met qualified teachers who have some strange ideas about their own language.

But, although 'I have been to London last year is grammatically incorrect, you will occasionally hear people say similar things.