A peer bullied a member of staff while on the way to "behaviour change" training, which itself was mandated in the wake of harassment claims against him, a watchdog has concluded.
Lord Lea of Crondall, who previously served as assistant general secretary of the TUC for more than 20 years, was found to have breached the House of Lords code of conduct in the latest report from the commissioner for standards, Lucy Scott-Moncrieff.
The complainant, known as QR in the report, said they felt "belittled and undermined" by the January 2020 incident.
Lord Lea has since written to QR to "apologise fully and unreservedly" for his conduct, explaining that he was "under some stress at the time" but the way he addressed them was "unacceptable and wrong".
Lord Lea is a non-affiliated peer, having been suspended by Labour in January following an investigation by the standards watchdog regarding his behaviour towards two women.
One woman described the peer as being "slightly stalkerish", while another said he offered to write a "sexually suggestive" poem that rhymed with her name.
This earlier report from Ms Scott-Moncrieff led to Lord Lea being referred for "behaviour change coaching", the reason why he was due to meet his guest, referred to as Dr K, in January.
Ms Scott-Moncrieff's latest report detailed how Dr K had not been allowed to enter Parliament as he did not have a booking and instead went to another part of the estate to wait.
QR said they reported this to Lord Lea who "became very angry, raised his voice" and told them to get his guest "back immediately".
A second, "somewhat calmer", exchange followed in which the complainant explained that Dr K's email as proof of invitation to the Lords was not sufficient for security reasons.
The report added: "QR reported that 'Lord Lea was incredulous that anybody could falsify an email, that it was possible or indeed that anybody would do it'.
"Again, QR explained the reasons for not allowing Dr K to enter but 'Lord Lea said that he did not believe me and that he would be taking the matter further and would be contacting my superior'."
In his response to the investigation, Lord Lea said he was "keen to apologise" in person to QR for "seriously upsetting" them on the day in question.
The report added: "Lord Lea explained that Dr K was his contact at the training providers contracted by Parliament to provide sanctioned training. This was Lord Lea's first meeting with Dr K after agreeing to remedial action in response to earlier complaints about his conduct.
"He was therefore anxious that the meeting went well and was distressed that arrangements had not worked as he had expected. He said he was already tense ahead of the meeting and, as this problem arose, he began 'to feel very anxious at the prospect of a total fiasco'.
"In his interview with us he emphasised this point about his anxiety at the time, saying: 'What was going through my mind right from the start is: this is a nightmare'."
The report added Lord Lea said he had not been angry but was "losing my cool, getting very agitated", noting he agreed it was reasonable for QR to interpret this as anger.
It also noted Lord Lea had discussed the incident with Dr K as part of his "behaviour change" training.
The report's finding stated: "This behaviour met the criteria for bullying, and was a breach of the code of conduct."
In his letter to QR, Lord Lea also wrote: "I am not known for being a bully: I acknowledge having been very argumentative, highly audibly so, on that fateful day, concerning the predicament I found myself in regarding the apparent disappearance of my newly appointed trainer and you said you had felt 'belittled' as a consequence.
"I have from that very afternoon been undergoing counselling and bespoke coaching on how to change my behaviour, and hopefully learned how to be far more measured and empathetic in my conduct in future."