At what point does public intimacy tip over from a touching display of innocent romance into offensive vulgarity? Jonathan Williams and James Bull found themselves on the front line of this moral conflict when when they were thrown out of a London pub for kissing.

Williams, a journalist for a financial magazine, and Bull, a charity volunteer, said they had been ejected from the John Snow in Broadwick Street, Soho, central London, on Wednesday by a woman – claiming to be the landlady – who accused them of being "obscene" while out on their first date.

The event has triggered a public debate on open displays of affection, how much is too much, and whether Williams and Bull were treated differently because they are gay.

The two men deny having behaved in any unseemly way. "We weren't being over the top; there wasn't anything that would be deemed unseemly," Williams said. "I'm not the kind of person to do that kind of thing in public."

While the management at the John Snow were unimpressed by Williams and Bull's embraces – which one bystander told the Guardian amounted to "snogging, but it wasn't heavy petting" – the lovestruck pair found rather more support on Twitter and Facebook, even inspiring plans for a "kiss-in" event at the pub next week.

Williams, 26, and Bull, 23, had enjoyed a dinner in Covent Garden before heading for the John Snow to indulge a shared passion – the pub's cider. "It's a nice little pub, it's a nice atmosphere," Williams said. The pub is near the heart of London's "gay village" but does not style itself as a gay bar. "The people are friendly, it's not too expensive considering the area and it's a decent pub where you can just relax," Williams added.

Their peace was shattered when a fellow drinker, who claimed to be the landlord, asked them to refrain from kissing because it was "bothering" him. Williams and Bull said they were not indulging in a "huge display of affection" but were merely kissing on the lips. The couple refused what they said was a "polite request" and their stay continued unhindered. At about 10.45pm, a woman who said she was the landlady intervened.

Bull said he was putting on his coat to leave and had given Williams "a peck on the lips" when the woman, who was wearing a staff uniform, came up to them. "She said we had to leave because we were being obscene. Then the other guy from earlier came over again and said we had to leave now, we 'weren't allowed to do that'." Bull and Williams said the man took hold of Williams's coat lapels as he asked them to leave the pub, and fellow drinkers joined in the pair's protestations of innocence.

Lucy Clements, a 27-year-old production manager, and Jamie Morton, neither of whom know Bull or Williams, were sitting at the next table and witnessed the events. Clements said: "I was totally shocked. Dumbfounded really. From a pub in the middle of Soho you just don't expect it."

She added that "no one seemed to mind apart from this one man". She said she spoke to bar staff who confirmed the man who raised the first objections was the landlord, before both she and Morton were also asked to leave.

Bull, who said he was physically sick after the confrontation, called police when he got home. They came and took a statement. "I felt so belittled, and to be made to feel so dirty and cheap over something like that – it's just wrong," he said.

Williams turned to Twitter to complain about the ordeal."Seven years in London & I've never been made to feel bad for being gay. 45 min ago the John Snow pub, W1F had me removed for kissing a date." His post was retweeted dozens of times and inspired the scheduling of at least two kiss-in events at the John Snow – one on Friday and another next Thursday. The Facebook page for the second event pledges: "Let's show them just how fun same-sex salaciousness can be when it's filling up the pub."

More than 200 have said they will attend, with one opportunist posting: "Of course I'm doing this for the principle, but there's a male friend I've always wanted to snog, and this is the perfect excuse."

The John Snow is one of about 300 pubs in the UK operated by the Samuel Smith brewery. Bull and Williams said they had not yet complained to the company, but planned to do so later. When the Guardian called the pub twice, a woman said: "Can you just stop calling this number please, or we'll have you done for harassment."

A spokeswoman for the Metropolitan police said: "Police are investigating an incident which occurred at approximately 10.50pm last night at a venue in Broadwick Street, W1. There have been no arrests and inquiries are ongoing."

The case is intriguing legally. The Licensing Act 2003 gives a landlord the right to eject customers. But the Equality Act 2010 says everyone must be treated equally in the provision of goods and services. For a successful defence against any legal action under the act, the landlord would have to prove he had ejected heterosexual couples for similiarly overt displays of intimacy.