Why Afghanistan needs the full chain
Some destinations accept a single UK certificate and ask for nothing further. Afghanistan is not one of them. Embassy legalization for Afghanistan from Manchester therefore has three parts, each done by a different party, and each one only valid because the one before it happened. The order is fixed: a notary, then the FCDO Legalisation Office, then the Afghan mission. Nothing in that sequence can be swapped or skipped.
The practical effect is that the paper spends most of its life in transit rather than on anyone's desk. That is why the route is quoted at 7–10 business days rather than as three short jobs added together, and why a missing notary seal costs more time than any other error.
What the Afghan mission adds
The final stamp is applied by Afghanistan's embassy or consulate, and it is that stamp — not the UK one — that offices in Afghanistan look for. The mission sets its own consular fee and its own opening arrangements, so this last leg is the least predictable part of the route. Embassy attestation for Afghanistan is only granted on a file that already carries the FCDO certificate underneath it.
The route, step by step from Manchester
Step one is local and can be done in a day: a notary public or solicitor witnesses and seals the paper. Step two is the FCDO Legalisation Office, which certifies that seal for £45 and works entirely by post from PO Box 6255, Milton Keynes MK10 1XX. Step three is the Afghan mission. Document legalization for Afghanistan is finished only when that third stamp is on the page.
Where the paper is a birth, marriage or death record, start by ordering a fresh certified copy from Manchester Register Office (Heron House, 47 Lloyd Street, Manchester M2 5LE). A new copy costs little, carries the same weight as the entry it comes from, and means the version in your own file never joins the queue.
Cost and timing for this route
The fixed part of the bill is £45 for the FCDO certificate. The consular fee charged by the Afghan mission comes on top and is set by the mission, so the total varies with what that fee happens to be. Timing is 7–10 business days for the standard route and 2–3 business days on the express route, with postage between the steps added to either.
Things people get wrong on this corridor
The commonest mistake is treating the FCDO certificate as the finish line, because it looks official and arrives with a seal. On this corridor it is the middle of the job. The second is sending a paper that was never notarised, which the FCDO cannot act on at all.