Grabbed by baton-wielding security officials during a recent anti-government protest in Sudan and reeling from teargas, Ahmed Mahmoud was beaten for an hour before he was tossed onto a pickup truck and taken to a building guarded by men in civilian clothes holding assault rifles. He and two dozen others were taken inside and pummelled for eight hours.

“They moved me to a location that was a school of some sorts but had been turned into a police station,” the 31-year-old filmmaker and activist told The Independent. “I was held by security and beaten repeatedly.”

Bruised, battered and terrified, he was finally taken to an official Khartoum police headquarters, where he was let out on bail. But rather than be deterred, Mr Mahmoud braved baton-wielding thugs to join anti-government protests in the capital on 6 January, and planned to take part in further protests this week.

“I will go again,” he said. “All these protests aim to deliver a memo to the government demanding the stepping down of Omar al-Bashir.”

Sudan’s leader came to power in a coup 29 years ago and has faced many challenges, including international isolation over his alleged support for militant organisations, criminal prosecution over war crimes allegations in Darfur, and demonstrations against his rule following the 2011 Arab Spring uprisings.

But the current wave of protests – which began 19 December after riots in the rural town of Atareb over the rising price of bread and spread nationwide – may be his greatest challenge yet, say observers.

“It appears as though this was the straw which broke the camel’s back and that discontent has been brewing for a considerable length of time,” Rob Bates, director of protective services at the London-based Blackstone Consultancy, a security firm, told The Independent in a note.

On Friday, hundreds of protesters were gathering after midday prayers, in Khartoum and in Sudan’s second city of Omdurman.

As the protests have mushroomed and continued, civil society organisations and opposition political parties have signed on, giving the movement more organisation and capacity.

“We call it the Sudanese revolution,” says Sara Abdelgalil, a British doctor of Sudanese descent who is part of the network of physicians and professionals that have taken up a leading role in the protests, especially in the capital, Khartoum. “People were not anticipating it will be that strong and be the main threat against the current government.”

“There is a united vision and a united movement to end the current regime,” she says, citing a nine-point list of demands that culminates in elections for a new government. “Where we stand at the moment is that people have requested the handover of the power peacefully. And are insisting on peaceful tools. The challenge is that the current government won’t give up easily.”

Mr Bashir appears in no hurry to go and seems willing to use deadly force to maintain his grip. There has been considerable violence during the protests, and while the government says 22 have been killed, tallies compiled by human rights monitors and activists suggest at least 48 might have died.

“Most of them are shoot to kill by snipers,” says Dr Abdeljalil.

This isn’t about livelihoods and food prices – this is about Bashir and his government stepping down Zeinab, protester

In Omdurman, west of Khartoum, Zeinab, 42, a charity worker and protester who has participated in years of rallies in Sudan, described watching a man gunned down next to her during one of the marches in December.

She told The Independent that snipers lined the roofs of the buildings near the protests and were trained on the rallies.

The protesters are usually met with pickup trucks mounted with heavy machine guns and people have recently started seeing armoured vehicles.

Despite the threat of further violence, she was preparing to go out again this week.

“This isn’t about livelihoods and food prices – this is about Bashir and his government stepping down. The chants in the marches are ‘Step down, that’s it’,” she says.

“There are so many reasons: 80 per cent of our national budget goes to the military and armament – it should go on welfare. The wealth is not going to the people: it is going to pockets of [Bashir’s ruling party].”

“We feel our people are being sold like slavery,” she says.

Zeinab, who has participated in multiple smaller outbreaks of protests in the past, says that for the first time she has hope these rallies might succeed in dethroning Bashir.

“Firstly, it did not start in Khartoum. Also the reaction from the street is different. People are helping, encouraging – when that man was shot next to me employees of a bank facility sheltered us from the intelligence services when we hid.”

Mr Bashir, perhaps realising the sea change, appears to be trying to address some of the protesters’ concerns, sacking the health minister in recent days and promising to raise public sector wages. But experts say the country’s problems run much deeper.

Though the US last year lifted an economic embargo against Sudan, the country’s economy has worsened, with inflation rising and austerity measures angering a population already fed up over poor roads and transport networks, and failing education and health systems.

The country has been in dire straits since the 2011 cessation of oil-rich South Sudan, plunging oil sales from 389,000 to 95,000 barrels per day, and forcing Khartoum to turn to the International Monetary Fund, and abide by its cost-cutting measures.

Government efforts to thwart the protests by blocking access to social media, firing teargas, rubber bullets, or even live fire, and dispatching baton-wielding thugs against them appears to have failed. But Mr Bashir has weathered previous protests before. In 2013, his gunmen killed 200 protesters during a week of Khartoum protests.

“Whether the protests will become organised enough, widespread enough and supported enough to lead to a change of leadership in Sudan is something which is not yet clear,” said Mr Bates.