Actually, that is a fantastic idea.
It could automatically transmit your details to the immigration people and if you needed Special Branch clearance, also to the right department at the right police force.
I wonder who one might suggest that to?
Anybody who can do basic interactive web stuff can do this. A piece of cake. One would need to run some sort of prepay though because the back end will have to send a
fax (for sp. branch; the other two have emails IIRC) and that costs money. The cheapest way would be an email2fax gateway.
The real problem is liability. No third party is (understandably) going to touch this with a bargepole, commercially or otherwise, because if some GAR form (esp. re IOM/Ireland) fails to transmit (website fails, or the email2fax function fails) the sender could get arrested. I have failed to deliver GAR forms a few times because the fax # was duff, or the receiving machine was duff / out of paper, and if doing this with a website this failure would have to be communicated back to the sender, probably by
SMS. Just like homebriefing.com sends you an SMS on flight plan accept/fail. Again, email2sms is straightforward but not free so a prepay is needed for that as well.
Unfortunately, the Plod never confirm receipt electronically. You get a phone call with a "permission number" (they like to pretend that you need a "permission"), and this can be any number of hours later. So, even an SMS saying the transaction succeeded would not mean the fax was actually delivered.
And I don't know of an email2fax service which offers an sms confirmation (would be a nice feature). Such a feature would solve this problem because the delivery of the ultimate fax would be confirmed directly back to the sender, on a mobile # specified at the time of the filing. It would be as good as you filing the GAR form right now, using an email2fax service which sends you an email confirming the transmission. Actually it would be better because you could do it from an internet cafe, at which you cannot check incoming emails unless you use webmail....
The proper way to deal with this is for the Home Office to set up the website, and the back end would send the data via fax (paid for by the HO of course) or some other in-house method to the appropriate force. There would then be no need to report success/failure back to the sender because the website filing itself would be legally sufficient - e.g. the website would show a 'confirmation number'.