Source: http://www.theelectricbrewery.com/forum/viewtopic.php?t=25410
4 packs Wyeast 1968 London ESB Ale liquid yeast (or an appropriate starter)
-OR-
4 vials White Labs WLP002 English Ale liquid yeast (or an appropriate starter)
Some hop substitutions will still give you an enjoyable ESB, just try and stick with English (UK) hops if possible. You can (for example) make a very nice variant with only UK East Kent Goldings (EKG) hops as they're much easier to find.
Yeast substitutions should be avoided however. One of the keys to brewing this right is to use Fuller's own yeast which is available to homebrewers as Wyeast 1968 London ESB Ale liquid yeast or White Labs WLP002 English Ale liquid yeast.
This yeast does not attenuate very well so we purposely mash at a low temperature (148F). The yeast is also highly flocculant (likes to settle out) so giving the bottom a gentle stir once a day during fermentation can help it from falling out too soon.
Add 500mg potassium metabisulphite to 20 gallons water to remove chlorine/chloramine (as required).
Water treated with brewing salts to: Ca=110, Mg=18, Na=17, Cl=49, SO4=92
(Basically Randy Mosher's ideal Pale Ale numbers with slightly less Sulphate and a Cl:SO4 ratio of 1:2 - we're not making a hoppy American beer here so we go a bit easy on accentuating bitterness).
1.25 qt/lb mash thickness. Single infusion mash at 148F for 90 mins. Mashout to 168F.
60-90 min fly sparge with ~6 pH water. Collect 13.9 gallons in boil kettle.
Boil for 60 minutes. Lid on at flameout, start chilling immediately.
Cool wort to 66F and aerate well. Ferment at 66-68F until complete. Dry hop for 7 days.
This yeast drops brilliantly clear without need of any clarifiers.