Southwell Girlguiding commissioner pictured with long-barrelled gun and dressed in dominatrix gear

The chief executive of Girlguiding UK has said photos of one of its leaders posing with a gun and in dominatrix gear are being urgently investigated.

Monica Sulley, who describes herself as a trans activist on her social media accounts, was appointed lead commissioner for the Southwell division of Girlguiding UK earlier this year.

Her appointment followed the departure of previous commissioner Helen Watts, who left the organisation after stating girls had a right to female-only spaces.

Monica Sulley, who is transgender, found herself at the centre of a social media backlash this week after the photos emerged online.

Monica, who referred to herself as Mistress on her Instagram page, took over the role after Helen Watts, a supporting member of the Guides for more than 15 years, was expelled from the organisation.

She stated girls had a right to female-only spaces — specifically toilets, showers and accommodation — following the introduction of a transgender-inclusive policy.

Last night, Helen Watts tweeted her reaction: "In case you forgot, I was thrown out of Girlguiding, ostensibly for breaching the social media policy, when I objected to sex self ID.

"But posting inappropriate violent and sexual content on social media (that any girl could find) gets a self-identified woman promoted."

Angela Salt, chief executive of Girlguiding UK, told the Advertiser: “The safety and well-being of our members is our absolute priority. We follow rigorous recruitment and vetting procedures, have clear policies, and a volunteer code of conduct which volunteers are expected to follow to keep our members safe.

"Girlguiding is aware of concerns raised. We are looking into this as a matter of urgency and will provide the necessary support and action in line with our compliance procedures.”

The Advertiser has made attempts to contact Monica Sulley.