I echo what you've been told previously. Unless you know you want to go there to live and work, say nothing. You'll get in fine. I had a much worse conviction than you in the eyes of the law and world and I got in.

Another complication is that they might still have a record of your earlier travel to the USA, in which case disclosing to them would tell them that you had travelled without disclosing. They might make a point of banning you for a defined period before they will consider a visa application, but I doubt they would bother prosecuting you, as sending you straight home is much cheaper for the American taxpayer. They also consider robbery to be a crime involving moral turpitude, so that prison sentence might lead to them saying you need a waiver of ineligibility, which takes much longer to process. If you decide to travel on an ESTA without disclosing, they won't know.

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If you are to punish a man retributively you must injure him. If you are to reform him you must improve him. And men are not improved by injuries. (George Bernard Shaw)

If you've never disclosed, the US has no idea you have a criminal record, so how can your 'previous dishonesty' be found out? The official you meet at the border desk has no access to British criminal records, they can't just look you up and check.

Once you disclose, however, you'll be forever in the US database as a former criminal. If I was in your shoes I'd say nothing. 

HI, looking for some advice with travel to the US.

40yrs ago I received a sentence of 3yrs for Robbery. 3yrs after my release (serving 1yr) I got married and went on honeymoon to Florida, at that time everyone assumed that any UK citizen was eligible for the old Visa Waiver Program so it wasn't until they handed the cards out on the descent into Orlando that I realised that I was in danger of being denied entry so, stupidly, I didn't declare, had a great honeymoon and never thought about it again.(nor offended again)

Fast forward to today when, after working for the intervening years for three major US corporations, one of them decides they want me to take a week long business trip to the US. I've made a lot of progress in the last 30 odd years and (a) this is a big opportunity and (b) a lot of it has been based on being open with people with a need to know about my past. Admittedly mercifully few of them have been since the update to the RoAA which spent my conviction and has meant my current employer doesn't know.

My gut reaction would be to do it right and apply for an exemption as I'm unlikely to be given a visa, my dilemma is that, if I do that then it's probable my previous dishonesty will be found and I'll either be denied entry or potentially charged with a previous illegal entry.

I recognise this is a pretty specific set of circumstances but does anyone have any insights at all?