Tommy Robinson’s Unite the Kingdom rally failed to get the huge numbers it wanted to march through London, with police confident less than half joined his protest on Saturday compared with an event last year.

The far-right rally happened on the same day as a pro-Palestinian march, and the Metropolitan police said that 43 arrests had been made during the two events.

Police said 20 arrested had attended the UTK march, including nine for alleged hate crimes, while 12 people detained had been on the pro-Palestinian march, including two arrested for alleged hate crimes. A further 11 arrests were not said to be linked to either group.

In September, a similar march spearheaded by Robinson, whose real name is Stephen Yaxley-Lennon, drew an estimated 150,000 people to the capital. The Met estimated Saturday’s event drew 60,000 people, still a sizeable crowd for a British protest, but well short of the million or more attenders organisers were hoping for.

Among the arrests of those attending the Unite the Kingdom rally were several instances of alleged hateful insults directed at officers. One officer from a minority-ethnic background is alleged to have been told to “fuck off back home”, two were allegedly subjected to a term of homophobic abuse, and another officer was allegedly told “take your religion and fuck off”.

Two suspects already arrested on suspicion of other offences also allegedly racially abused officers, directing the N-word at them.

One man was arrested for actual bodily harm after getting on a coach about to take pro-Palestinian protesters home and allegedly punching someone in the face after being told to leave.

Other arrests included three for holding placards, including ones that said “fuck Islam” and “Christ is king, fuck Islam”. Earlier the crowds had been led in a chant of “Christ is king” from the stage.

A woman was arrested close to the King Charles roundabout in Whitehall for possessing an offensive weapon, namely a sword approximately 3ft in length. One onlooker on the march described her as being in costume as an English soldier, and said the woman complied with police.

The Met said five officers had allegedly been assaulted and none had required hospital treatment.

Saturday’s far-right protest involved much less hostility to police than the previous one in September, when more than 20 officers were allegedly assaulted, with more than 50 suspects still being sought for a variety of allegations.

On the stage, Robinson, who compered the event, denied his was a far-right movement, saying: “We are a cultural movement.”

He has spoken about having converted to Christianity after a spell in prison last year, and the event featured Christian iconography such as crosses. The crowd were invited to recite the Lord’s prayer.

Police believe the number of arrests was relatively low given the size of the crowds, and the Met said both events had “passed off without any significant incidents”.

Also taking place on Saturday was the FA Cup final at Wembley, where 22 arrests were made.

At the pro-Palestinian march, one person was arrested for holding a sign reading: “Globalise the intifada”. It is alleged to be a call for violence against Jews. Another person was arrested for a sign pledging support for the proscribed group Palestine Action, and another for a sign reading: “We will not surrender, victory or martyrdom”.

Police are studying a further seven videos of written slogans and chants in case they cross the criminal threshold of anti-Jewish hate speech, amid claims police are stifling legitimate protest.

The Met say the pro-Palestinian march, which included anti-racist counterprotesters to the Robinson-led march, numbered 15,000 to 20,000. March organisers claim 250,000 attended.

Police placed tight conditions on both events, with speeches from their stages watched for any potential offences. A stunt on the UTK stage, in which three people appeared in burqas, bemusing the crowd before revealing themselves to be white women, has been judged not to be a criminal offence.

The Met deployed 4,000 officers in total, with some brought in from other forces, in what they say was one of their largest operations in recent years.