BANGKOK - A 30-minute drive out of central Bangkok lies the heart of Thailand’s latest orange obsession.

A seven-storey building, at the entrance of a narrow street in a residential neighbourhood, houses the Move Forward Party headquarters. With no large sign or even its distinctive orange logo out front, there is little evidence that this is where the party’s stunning win in Sunday’s general election was devised through many hours of planning.

The biggest winner, Move Forward claimed 151 of the 500 seats up for grabs in Parliament’s Lower House, according to unofficial tallies by the election commission.

Should official results and ongoing talks to form a coalition government support this mandate, the seven-storey building will likely be the home of Thailand’s main ruling party.

“I still can’t believe the results,” said Ms Supapan Palangsak, 52, who manages the shop selling Move Forward merchandise in the building. “We were all celebrating right here that night.”

The party’s reformist policies, which call for the end of military conscription, legalising same-sex marriage and amending the law against royal defamation, have often been thought to be too radical for mainstream Thai politics.

But after it won the largest share of the popular vote, the Thai people’s desire for change is clear, said analysts.

On Tuesday morning, reporters camped in the lobby of the Move Forward headquarters, with cameras and microphones set up for possible interviews and press conferences, or to capture any development in ongoing negotiations to form the next government.

Leader Pita Limjaroenrat, 42, and other party executives are trying to assemble a coalition of 309 MPs from six non-military affiliated parties, including the Thaksin Shinawatra-linked Pheu Thai Party.

With redbrick walls and New York loft-style decor, the building is the main destination for meetings, press conferences and – as evidenced from the well-stocked bar at its second-floor cafe – party celebrations.

Much like a typical start-up, its conference rooms and offices are named, and its chosen theme speaks volumes of the party’s message and policies.

One is called Rosa Parks, inspired by the American civil rights activist, another bears the name of Pakistani education activist Malala Yousafzai. There is also the Nuamthong Praiwan room, named after a 60-year-old Thai who crashed his taxi into a tank to protest against the 2006 military coup.

A picture of Mr Thanathorn Juangroongruangkit, leader of the dissolved Future Forward Party that preceded Move Forward, hangs on a pantry wall.

The party used to have about 50 MPs, but has tripled its size. It now has the most seats in the Lower House, giving it an advantage in establishing a government.

“Party gatherings will definitely be a bit of a squeeze from now on,” said deputy party leader Sirikanya Tansakun, 42, who is part of the team negotiating with the allied parties over forming the coalition government.

Hours after Move Forward’s win, Mr Pita staked his claim to being the country’s 30th prime minister.

But he and his party’s executives know that the road ahead is challenging.

Installing Mr Pita as the head of government will require majority support from Parliament, which includes the backing of the royalist, pro-junta appointed 250-seat Senate.

In the 2019 election, the Senate voted overwhelmingly in favour of former coup leader Prayut Chan-o-cha for prime minister. Several senators have already indicated that they might not support Mr Pita’s bid to be prime minister.

“We have been getting mixed signals, so it’s still a hurdle for us to get over. But the people have chosen, and we hope to use the pressure from voters to send a message,” said Ms Sirikanya, before apologising and rushing off to what one could only presume was another party meeting.

Meanwhile, the building is busy for another reason. Supporters have been crowding the Move Forward merchandise store to get their hands on shirts, water bottles, bags and books, emblazoned with the party’s logo.

“These are for my girlfriend,” said Mr Wathid Sorntong, 30, who bought a shirt and a hat. “She lives in another province, so I came to buy these for her.”

Ms Phornpimon Tongmauem, 24, left the shop with about two dozen shirts. She said: “I posted on social media about the shop and some people from upcountry wanted me to take their orders.”