Motorway gantry sign
A gantry spanning the motorway with blue overhead signs showing the following text.
Forward destinations: Preston, Wigan, St Helens; Leeds, Mc'r (N) (M62) M6 .
Exit destinations: M62 Liverpool, Warrington (N); Southport (M57) [Hollow square diversion symbol] [Solid diamond diversion symbol] .
Junction number: 21A.
There are two exits at junction 21A, both for the M62, and this exit is only for the westbound motorway - but you could be forgiven for not noticing "(M62)" lurking at the bottom of the sign here.