The commission said the UK was already collating names of perpetrators and would impose sanctions “including preventing people from obtaining UK visas or imposing sanctions under our human rights sanctions regime.”

In a statement made available to our correspondent on Wednesday, the high commission said, “We can confirm that we are collating relevant information, with a view to taking action against some individuals.”

The high commission, which said it deployed observers in six states, noted, “There were notable points of concern.  Members of our observation mission personally observed violence, and voter suppression in numerous voting locations. We witnessed and received credible reports from other observer missions and civil society organisations of vote buying and voter intimidation, the destruction and hijacking of election materials and the general disruption of the process in numerous states including Lagos, Enugu and Rivers.

“In addition, we observed incidents of harassment of journalists. Freedom of speech and a free press is crucial for a healthy democracy, and journalists must be able to go about their work without being threatened.

“The UK is concerned by the use of inflammatory ethnoreligious language by some public and political figures.  We call on all leaders not just to distance themselves from this kind of language, but to prevent those who speak on their behalf from doing so in this way.

“It is a testament to their commitment to democracy that many Nigerians were prepared to vote despite being faced with intimidation and hostility.”

It, however, commended the Independent National Electoral Commission for improving on its performance during the governorship and state Houses of Assembly elections on March 18.

The UK’s Minister of State for Development and Africa, Andrew Mitchell, gave the advice in a statement made available to our correspondent on Tuesday.

Mitchell noted that the UK and its government remained committed to supporting credible and inclusive elections, which are fundamental to Nigeria’s continued democratic growth and to the future of regional and global democracy.

He, however, urged party officials to respect electoral laws and institutions and avoid hate speech.

His statement read in part, “Nigeria matters to the UK, and we are following the run-up to these presidential, National Assembly and gubernatorial elections very closely.

“Over the last two months I have met four of the presidential candidates and the Chairman of INEC, and emphasised our support for the process and our commitment to a strong relationship between our two countries.

“The UK government continues to work closely with INEC and our Nigerian civil society partners to provide advisory support on electoral and legal reforms, assist in strengthening democratic institutions, and advocate  the importance of civil society engagement in electoral and democratic processes to help deliver credible elections. “It is vital for Nigeria’s stability and democratic consolidation that the electoral process is free, fair and credible. I encourage all actors in Nigeria to intervene proactively to calm any tensions and prevent violence in the periods before, during and after the elections”

The minister added that the UK was ready to take actions against anyone involved in anti-democratic behaviours.

He said, “Where the UK is aware of attempts to subvert democratic processes at the national or state level we are prepared to take action against those who engage in or incite electoral violence and other anti-democratic behaviours. These actions could include preventing people from obtaining UK visas or imposing sanctions under our human rights sanctions regime.”

Meanwhile, ahead of the polls, the UK announced that it would be closing its visa application centres in the Abuja, and Lagos on Friday and Monday.

The UK Visas and Immigration gave this announcement via its Twitter handle on Tuesday.

According to the UK, no VAC appointments will be booked, but customers can purchase the Keep my Passport in order to retain their passport during the period of closure.

“UKVI will continue to make decisions on all visa applications.

Priority Visa services remain available. Super Priority Visa services will be suspended on Wednesday 22nd and Thursday 23rd because the next working day opening is not until Tuesday 28th.

“Customers should not attend the VAC unless they have been contacted by TLS to do so. The British High Commission Offices are not involved in visa decision making and do not hold passports and so are unable to assist,” the advisory added.