Currently there are direct flights from Ibiza to United Kingdom:

Ibiza to London Gatwick
Ibiza to London Luton
Ibiza to Birmingham
Ibiza to Manchester
Ibiza to London Stansted
Ibiza to East Midlands
Ibiza to Belfast International
Ibiza to Newcastle
Ibiza to Bristol
Ibiza to Cardiff

Flights from Ibiza to United Kingdom with one stopover.

Flights via Barcelona (BCN)
From Ibiza (IBZ) with Vueling Airlines
OR
From Ibiza (IBZ) with Iberia Airlines
Transfer at Barcelona (BCN) Then on to London Gatwick (LGW) with Vueling Airlines
OR
Then on to London Gatwick (LGW) with Iberia Airlines
Flights via Madrid (MAD)
From Ibiza (IBZ) with Air Europa Airlines Transfer at Madrid (MAD) Then on to London Gatwick (LGW) with Air Europa Airlines
Flights via Alicante (ALC)
From Ibiza (IBZ) with Iberia Airlines Transfer at Alicante (ALC) Then on to London Gatwick (LGW) with Iberia Airlines
Flights via Dublin (DUB)
From Ibiza (IBZ) with Aer Lingus Airlines Transfer at Dublin (DUB) Then on to Birmingham (BHX) with Aer Lingus Airlines
OR
Then on to Manchester (MAN) with Aer Lingus Airlines
OR
Then on to Blackpool (BLK) with Aer Lingus Airlines
Flights via Amsterdam (AMS)
From Ibiza (IBZ) with KLM Airlines Transfer at Amsterdam (AMS) Then on to Birmingham (BHX) with KLM Airlines
OR
Then on to Manchester (MAN) with KLM Airlines
Flights via Oslo Gardermoen (OSL)
From Ibiza (IBZ) with Norwegian Airlines Transfer at Oslo Gardermoen (OSL) Then on to Edinburgh (EDI) with Norwegian Airlines