It's hawkweed - grows in places with sandy soil, and in neglected, under maintained lawns. Treatment with Resolva lawn weedkiller in spring next year will hopefully get rid of it, but it may return, so combine the lawn weedkiller with some lawn maintenance such as aeration, scarification and regular fertilisation during the growing season.

https://thelawnman.co.uk/orange-hawkweed-pilosella-aurantiaca/

And if you can get rid of it, come back and tell us. We have been killing it off for 20 odd years now.

Orange Hawkweed, otherwise as per Bamboo. A pretty plant but can be invasive. You can grow them in a border if you keep tight control.

Thanks to all for the information and advice, it looks like being a long campaign to get rid of it.

Also known as ''Fox and Cubs''. Fascinating plant and I have to admit that someone gave me a couple of these in a pot but I quickly got rid of when I realised just what it was.

I have them in my garden but I keep them as I think they are pretty, such a lovely orange flower :o)) I just keep them under control, I took a lovely pic of them once, they looked lovely :o)) I just take the flower head off before it goes to seed, ones in the lawn I zap with weed gel :o))

Its very prone to blackfly - wonder if it would keep the off the broad beans...(wrong timeof year though)

Just to say thanks for the other 3 comments, so far I have started the campaign using resolver and will continue with Weedol in the spring.

Just to update the helpful members who advised me on how to get rid of Orange hawkweed. I sprayed it with Resolver Lawn control and also used 'Roundup' on some of it, on the basis that it poisons the plant down to it's roots. As Hawkweed is a plant that spreads by root as well as seed, I reckoned that the poison might spread through the root system. The downside is that 'Roundup' is very expensive. I also reseeded parts of the lawn after raking out any diseased Hawkweed.

The lawn is now looking a lot better, but much work remains to be done and I think it will be a year or two more before I eliminate all of the Hawkweed, indeed it may prove to be a perennial problem. Thanks again for all the advice.