Help wanted identiying regiment from uniform

[AllanUK]

I'm wondering if he signed up during WWI

Yes.
His Medal card shows he received the BW & Victory medals.

Find My Past hold a service record for this man. It shows:

Residence --  3 Button Street, Frome, Somerset
Age -- 19 years 2 months
Height -- 5 feet 6 inches
Eyes -- Blue
Hair -- Light Brown
Complexion -- Fresh
Next of Kin -- Joseph Lay (father)
Date of enlistment -- 5/2/1916
Regiment -- 20th Battalion, King's Royal Rifle Corps
Joined battalion -- London 7/2/1916
Embarked -- Southampton 27/3/1916
With British Expeditionary Force -- 30/3/1916
To 20th Infantry Base Depot, Etaples, France (from 'In the field') -- 5/5/1916
8/5/1916 -- Transferred to England (under age) Authority CR No 5544/3270/A, dated 2/5/1916
His Statement of Services form states 19/5/1916 Discharged having made a mis-statement as to age on enlistment Para 392 VI King's Regulations

His record confirms that he was awarded the British War Medal and the Victory Medal.

If deejayEn has access to Find My Past, the link below will take you to his record.

https://search.findmypast.co.uk/record?id=gbm%2fwo363-4%2f007276714%2f02409&parentid=gbm%2fwo363-4%2f7276714%2f236%2f2409

[jim1]

There were plenty of underage boys who fought in the war
the youngest I'm aware was 15 but 14!
He must have been pretty much the youngest recipient of campaign medals.
You can discount the first photo but the one in tropical kit could be him.
He's not wearing his ribbons so may be taken before he received them
in 1920-21.
His helmet plate is too indistinct to id his Regt.

[deejayEn]

Thanks to both of you but the medal recipient is the wrong Albert Lay, mine was from London, Kentish Town and his dad was Walter.

That is my Albert Lay in the sepia photos but I'm trying to see if anyone agress with me that it is also him on the right in the top photo.

Also can anyone yet confirm whch regiment the two soldiers are in?