Early position raiser you have tagged as LAG - without knowing any more detail, he could potentially have any two cards here..... so 2 pair isn"t out of the question.
I wouldn"t have thought he would have QQ as if the table is so loose, one might expect a re-re-raise preflop..... but 77 or 44 are possible.
If he"s hit 2 pair or trips on the flop, with all those spades out there, he"s going to want to protect it....
But, if he had raised with AKo, including the A clubs, he"s probably going to be looking to gamble here with overcards and nut flush draw.
Whatever he has, he certainly doesn"t have the nuts already, and I doubt he has a flush at all...... so his all in move is either protection or big draw.
You have big hand, but with not much chance to improve... and you may already be almost drawing dead. Whether to call or not depends on your mood, and how much you value the £100 stack.... if you are the type of player who needs to find out if you"re being bluffed or not, then the call is a reasonable one....... but also, if you"re a tight assed bugger, the fold is equally good here.
I would call. I think he has Ace clubs, with either a K or a Q of another suit.