I've been working on my front derailluer and have recently come across a problem. When in the highest gear, the chain still won't move on to the top set of teeth. I'm pretty sure this is because there is not enough tension in the inner wire of the front derailleur cable. I've tried to tighten it at the anchor bolt, however, I can't get it tight enough even when I set it to the lowest gear. Does any one have any suggestions on how I can tension the inner wire further? Thanks.

Have you adjusted the limit screws? That seems more likely than cable tension to me.

+1.....sounds like the high limit screw is out of adjustment to the point that the derailleur can't move the chain far enough outward to shift to the outer ring-

Park Tool explains it better than I probably would (and they offer pics too!):
https://www.parktool.com/repair/readhowto.asp?id=75

Well my problem is that the high limit screw is already loose so much that a quarter of an inch of thread is exposed. I have also looked at the height and angle of the derailleur and those adjustments are correct. Therefore I'd have thought it would be to do with cable tension (there is only an inch and a half of wire exposed above the anchor bolt).

Means nothing. The wire is cut to whatever length the installer wanted.

I've adjusted the H limit screw to as far out as it will go and it still won't move in to top gear. The angle and height of the derailleur is correct. Any suggestions of what else I could do? I have looked at Park Tools and my chain is rubbing against the outer cage plate. It suggests loosening the adjusting barrel but I am unsure of where the adjusting barrel is with my Campagnolo gear levers.

Take hold of the cable at the down tube and pull it firmly down. Does the front derailleur now position itself over the big chainwheel? If so then the fault would appear to be with the cable or the amount of cable taken up with the gear lever. If the cage does not move out enough then has the Bottom Bracket been replaced with a longer one which would cause the chainwheel to be too far out for the cage to reach.

As far as cable tension, the cable should be pulled taut with the derailleur in the low stop position, nothing more. Fine adjustments can then be made with the barrel adjuster if necessary. It's kind of sounding like your front derailleur doesn't have the range of movement necessary to shift to the outer ring. Is it a derailleur originally intended for a double crank and you're using it with a triple? Sometimes this will work, sometimes not-

It is a double crank and the derailleur came with the bike as new.

Yes the fault is definately with the cable. The problem is when I loosen the anchor bolt I can't increase the tension in the inner cable any further. Does any one have any ideas on how I could do this?

Ok, too much speculation and no answers-

You have to hold the derailleur cage OUTwards and THEN tighten the cable on. You'll never get satisfactory cable tension otherwise.

The other option is to use the Low adjustment screw to hold the derailleur OUTwards the middle chainring (so you don't have to hold it there) and then tighten it.

And when I say outwards, I mean away from the bike, as in moving towards the middle and big chainring.

Not true at all.

I agree this is not correct. The initial cable tension is set with the derailleur inward against the inside limit screw stop and (VERY important) the shifter set in the most inward and relaxed position.

If its a STI or Ergo, push the release lever or button several times to be sure the shifter is in it's lowest gear setting before reattaching the cable.

What make of derailleur is this? Is there a shallow groove on the end of the upper arm (cable attach) If there is a groove there ala Sora 8 speed, then the cable goes through that groove before being attached under the screw. This will provide more travel to the front derailleur. If there is no groover, is your cable going undet the part of the screw father from the pivot?

Are you tensioning the cable with the low adjustment screw in the correct position? The cage should just be missing the chain when in the inner chainring/inner rear cog)

You people amaze me. The OP has trouble getting cable tension, and you're still harping the same garbage as before?

OK, be amazed but did you read what I really recommended?

I expect the cable was initially hooked up with the shifter not in the lowest gear position. That would easily explain the lack of travel and being unable to get to the big ring.

OP, to answer your question:

Follow the cable from the FR der, under the frame, and up the downtube until the bare cable runs into the housing that leads to your bars. At that juncture, there is a barrel adjuster. Give it a turn to the left and try shifting again.

You may have to do this a few times to get it right.

I suspect this is a new bike and it was fine when you bought it but has developed this problem? If so this is normal with a new set up. You should start having the same problem with the rear der soon, as well. One these are set yo should be good for quite some time.

If you continue to have problems some more detailed info about your particular bike would be helpful.