losing spark while cranking.

Hi folks, can someone help? Freelander 1, 1.8 would not start first thing this morning, it turned over and offered to fire for a second or so then just turned over with no sign of firing up. Have checked for fuel supply and it's ok, have fitted brand new spark plugs, rotor arm and dizzy cap. Checked for spark and find that it is strong/bright for a second when key is turned to crank position but it quickly gets weaker and dispapears completely after a few seconds of cranking. Any ideas, as we are desperate to get car running asap.

coil pack?

I thought obout the coil, but i tried a spare coil i have for a series 111 and i get the same results!! what about the ecu? would it cause this?

Does the fuel pump keep working to supply fuel? wondering if you have an immobiliser issue

It could also be a ignition switch fault. Try turning the ignition key to the second position and then applying a direct feed from the battery to the fly lead connector on the starter motor (or short across the terminals if yer happy to do that). If it starts then, it's likely to be the ignition switch breaking down.

Getting fuel, pump working, plugs wet due to not firing up. Tried a spare ecu my mate had for an old rover214 he used to have, sparking great while cranking now but only starts and runs like a bag of bolts for a few seconds then cuts out. Will try get proper ecu tomorrow and see what happens? Thanks to the folks for suggestions, will keep you updated.