A memorial to German philosopher Karl Marx has been vandalised for the second time this month.

The words "Doctrine of Hate" and "Architect of Genocide" were daubed in red on the grave of Highgate Cemetery's most famous resident.

The latest episode follows a hammer attack on the monument in north London two weeks ago, which prompted the charity which runs the cemetery to lament that the memorial "will never be the same again".

Maxwell Blowfield said he was "quite shocked" to see the vandalism when he visited the cemetery on Saturday morning with his mother.

Mr Blowfield, 31, who works as a press officer with the British Museum, said it was particularly sad as tourists regularly visit the site.

"It's a highlight of the cemetery," he said.

"It's a shame. The red paint will disappear, I assume, but to see that kind of level of damage and to see it happen twice, it's not good.

"I wouldn't like to say who or why someone did it but it was clearly someone very critical of Marx and that part of history. I am just surprised that somebody in 2019 feels they need to and do something like that."

Following the hammer attack on the marble plaque of the memorial on February 4, the Friends of Highgate Cemetery Trust said it was clearly a "deliberate and sustained attack".

Ian Dungavell, the trust's chief executive, said that incident of vandalism on the Grade I-listed monument, which puts it on a par with the most important buildings in the country, was "very upsetting".

The plaque was first used on the grave of Marx's wife, Jenny von Westphalen, in 1881 and was moved when the remains of Marx and his wife were exhumed and reinterred in a more prominent location in the cemetery in 1954.

The monument is owned by the Marx Grave Trust, which is represented by the Marx Memorial Library in Clerkenwell.

Police confirmed no arrests have been made over the February 4 attack.