Oh dear Daff this looks like Mares Tail a weed thats difficult to get rid of .

As you can see they are very successfully designed to penetrate through ground that has poor drainage , due to its leaf it doesnt absorb weedkiller easily and has roots that can go down over a metre .So things that claim they kill to the root cant travel that far.Tops are easily snapped off but the root system is very resilient.

Repeated digging does seem to loosen its grip , there are fossilised examples of it so shows how tenacious it can be.

I have to agree with Bonkersbon.

isn't it said to have been around at the time of the dinosaurs

That's interesting. Do you think it was food for some creature? Should we resurrect a dinosaur for hire?
There have been other questions about this, You could check it out on the site.

as long as its only dino--- from the flintstones, I couldn't cope with the big ones I have enough trouble from the rabbits :o)))

Marestail (equisetum) can travel down many many metres....
If spraying with weedkiller, I've read that that badly bruising it beforehand helps the absorption. It's the high silicon content that makes it resistant.
Handfuls of it have been used as pan scrubbers....... Good luck.

Thank you very much

http://www.allotments.fsnet.co.uk/marestail.html
The link above gives excellent advice on getting rid of your weed. In case you cannot access it I have copied the fact sheet for you
Fact Sheet – Horsetail
Horsetail, Equisetum arvense, is a perennial plant also called `marestail' or `pipeweed'. It is an ancient relic of primeval times -a link between modern plants and extinct orders. Many of our coal measures are composed of fossilized remains of immense equisetum-like plants - forests of which once covered the earth.
Description
Equisetum can be found on all types of soils. It grows from an underground stem or rhizome, and produces two types of above-ground stem. Brown 'fertile' stems emerge in the spring and these are topped with a cone-shaped structure which produces spores. These spores only develop in very moist situations and are rarely important in a garden situation.
When the fertile stems have died down, brush-like, green vegetative stems emerge. These are rich in silica so have a tough, wiry feel (they were once used to scour pots and pans). There are no true leaves; the characteristic bushy appearance is caused by whorls of branches up the stem. The underground stems or rhizomes are black in colour. They can penetrate deeply into the soil and are the main means of spreading. When these stems are broken-up, individual pieces will regrow very readily in the same way as couch grass.
Prevention and control
digging it out: really not a viable proposition unless you only have a small patch and a lot of time!
Shading: as they do not have significant leaves, horsetails do not compete well with vigorously growing crops. In the vegetable garden a couple of crops of potatoes, for example would help to control this weed. A tall growing summer green manure, such as Phacelia tanacetifolia or buckwheat, might be an alternative. One reference states that a crop of nasturtiums will smother it out, but this is not something we have tried. It will take several seasons before the weed is controlled.
· Hoeing off the tops: another reference says that continual removing of the tops should kill off the weed in 3-4 years. A combination of hoeing and growing a smothering crop might well be a good method to try.
· Mulching: a heavy, light-excluding mulch can be used around ornamentals to keep this weed in hand. Try newspaper or cardboard, covered with woodchips, bark or leafmould to make it look more attractive.
· Improve the soil: horsetail tends to thrive in poor conditions, so improve the soil by adding plenty of organic matter.

Horsetail tea
Biodynamic growers use horsetail tea to strengthen plants' resistance to fungal infections. Take ¾ oz dried horsetails and simmer for 30 minutes in 2 pints of rain water. Stand for 24 hours. Make up to 1 gallon, stirring the mixture for about 15 minutes. This mixture will keep for a couple of weeks. Spray the plants thoroughly every 10-14 days, starting early in the season. The later sprayings can be more dilute (making the solution up to as much as 10 gallons) but should always have a pale yellow-green or brown colour and smell of horsetails.

Thank you scots gran - I will remove the spore heads for a number of years and see what happens !