for some the answer is to move house !
If you have the determination you can make an inroad into it. If you bruise the stems first then spray with glycophosphate it is absorbed better. Dont let it 'flower' either. repeat this regularly through out the growing season and one in late summer too.
good luck with it.
welcome to GoY too.

I have it too and did as Sbg suggests by bruising it towards the autumn just before it dies back and applying the glyphosate with a rubber glove. Doing it then means that it takes more of the glyphosate sugar down into its roots.

I have little bits around my garage. The advice given above works to keep it in controll

I have it too I find the more I pull it up the less it gets, but I never get rid of it. I find I cannot treat it as its right in among the plants.

When we moved into our present house the driveway was covered in mares tails, we just kept pulling it and pulling it and eventually it decided never to come back.

We have mares tail throughout the lower part of our garden, and have found glyphosate to be totally useless.
It cannot be dug out as the roots go down for metres.
It will disappear if it is regularly mowed out in grass.

I covered one area of the garden with black plastic which was left in place for two years. When I moved the sheet and started cultivating the soil, it came back.
The only area we defeated it was the patio which we covered in geotextile and gravel. The mares tail still came through the geotextile, but by pulling out every piece for two years it eventually disappeared and gave up! Hurrah!

In the end, we've found just pulling it out regularly, especially when you can remove a large stem later in the summer, it can be kept under control.
There are worse weeds, such as Japanese Knotweed, but not many.
You can live with it, and it doesn't seem to hinder the growth of vegetables. I've heard it said that growing turnips will deter it, but haven't tried it experimentally yet.

We haven't found anything that really works either and have tried everything , like Drc says it gets right in the centre of the plants where you can't get at it , it's creeping in out garden from an overgrown vacant field next to us which is covered in the stuff , we have put down carpet squares covered it in bark also membrane where we have gravel , it still manages to break through .........

i have heard on the bbc radio that planting turnips in the area with the mares tail will stop it in its tracks, it cannot tolerate the turnips.

Interesting?.....

Is it April 1st ... LOL....

Turnips don't work.