Leylandii - sorry! I need advice

We have the same problem with our boundary. 40 odd years ago, our neighbour planted about 20 minature Leylandii, or so he thought.
They grew to a terrific height then had about 20ft cut off the tops. He kept them under control for many years.
After he died, his nephew inherited the house and rented it out. He never bothered to cut the trees and up they grew again.
I looked on our local authority website for all the legal information and decided to send the owner a nice letter requesting that the trees be pruned. He ignored it so I sent another, recorded delivery, which was ignored again. Third attempt, when I suggested we go to arbitration as per the ruling in the guidance on dealing with problem hedges on the council website (quoting pages and paragraphs and including a link) had the desired effect.
I kept copies of all my letters and photos too.
Good luck.

Thanks for your advice. I went round to the house and spoke to the tenant, who would also like to see the leylandii reduced in height. We agreed that I would pop a letter through his door and he would pass it on to the owner. (She is, shall we say, difficult. A couple of years ago her fence smashed into my greenhouse and she refused to take any responsibility). So, in the face of what could be a protracted battle I have decided to look into gadgets which sonically repel birds such as parakeets and pigeons. I believe that the council are only able to impose a fine of £1000 if she doesn’t cut the trees. That’s nothing to her, so I don’t hold out a lot of hope that they will be reduced in the next few years. Thanks for your advice - I was scared of potential unpleasantness and it hasn’t happened.

Parakeets in the UK? Making me shiver lol!

Sorry, I should have added that yes I am in the UK

Thank you all. Yes, I think I will pluck up my courage and go and see them.
The council rules appear to be that I must’ve tried to contact them first before applying to the council. Many thanks, to you all

It’s a big job and will be expensive, so it might help if you offer to share the cost.

2metres seems to be the height quoted when I google.

I would try and have a word with the neighbours first. As Bluebelle said, you could write a note. They may be lovely and just cut them. They may be unreasonable and then you could contact the council.
If was your neighbour I would prefer it if you spoke to me first.

There are laws in the UK on Leylandii heights, which country are you in? Find out what laws are in place regarding this.
Then, go and ring their bell, introduce yourself and explain the problem.If done politely they shouldn't take offence.
If all else fails, phone your council, and explain the problem, and they should take action.

I would contact the local authority first- they have guidelines and could let you know what your rights are, particularly regarding the parakeets which could be a health hazard.

If the trees are blocking your light you can have them cut down (in the UK at least).

I would be tempted to write a friendly note, especially as you don't know them and introduce yourself. Maybe offer to help find a tree surgeon, and even bear some of the cost if they are not very well off.

Why not send a friendly letter instead of knocking on the door

At my previous house there was a Leylandii hedge belonging to the neighbour.
I was having a similar problem with birds. I spoke to my neighbour and explained the problem. Luckily he was reasonable and agreed to have it cut, which he did.
If you are worried about asking in case they turn nasty do you have a friend who could come with you?