Anyone recognise this plant?


Hi, I found this long trailing plant in the wooded area of our garden. The wood's neglected so it's been there a while and is scrambling up the trees for about 6 metres plus. There's a few of them.
Does anyone recognise it?
Not the ivy (!), the long plant stem trailing around the edges of the picture. I realise there's not much to go on as it's only just budding. It seems to have a flexible wooden stem about an inch or so thick and is just staring to bud small pale lime-green leaves. There's a few elderberries nearby but I don't think it's that. It seems to be scrambling up the holly, ivy, sycamore/ash/beech trees.
Grateful for any views, I've learnt the hard way it's best to know what the plant is before you decide to leave it in, in case it's a particularly invasive weed....
Thanks.!
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Can'tsee very well but wonder about Clematis vitalba, Old Man's Beard
In the sticks near Peterborough
Morning nut!
I agree - it does look like a clematis stem and the little I can see of the emerging leaves seems to match. 
You're spot on, I just googled for a pic of Old Mans Beard and found a video of a Professor talking about it - it matches the stems.
Thanks, very impressed.
My dilemma now is whether to keep it, there seems to be a few articles online about it being great for wildlife but bad for trees. Many of the trees in our wood are in decline after years of neglect and over the next few years I need to clear the dying and look after the rest ....
Cut it right back to start again, if you do that from time to time it won't take over the world. It won't die whatever you do to it. I know
In the sticks near Peterborough
old mans beard - ummm