Boris Johnson has urged the Welsh Conservatives to build on their general election success to take power in Wales at next year’s Senedd election.
He told activists in Llangollen the Tories were a great one-nation party representing deprived communities as well as leafy suburbs and market towns.
“We speak proudly now for people whose families have never voted Conservative for generations,” he said.
“We will represent them well and we will repay their trust.”
The Conservatives won six seats from Welsh Labour in December, giving it 14 MPs in Wales and its best result since 1983.
Mr Johnson pledged to invest in education, infrastructure and technology to “spread opportunity” and “transform the fortunes of our entire country”.
He said it was “not just the right thing to do, but the economically smart thing to do”.
Looking ahead to the Senedd election, Mr Johnson said it would be “fantastic” to have a Welsh Government that properly served the interests of the people of Wales, instead of Labour under First Minister Mark Drakeford.
“Let’s get ready for 2021 and let’s make sure Paul Davies and his team show the desiccated Corbynista Drakeford where to get off,” he said.
Welsh Conservatives in power would deliver vital transport improvements he claimed were being ignored by Welsh Labour, such as the case for an M4 relief road rejected by Mr Drakeford.
Referring to the regularly congested Brynglas tunnels in Newport, Mr Johnson said: “Let’s unblock the nostrils of the Welsh dragon with the Vicks inhaler of one-nation Welsh Conservative can-do spirit.”
Earlier, the Tories’ assembly group leader Paul Davies pledged to “end the assembly gravy train” if they win power at the 2021 Senedd election.
He pledged to halve the number of Welsh ministers to seven, freeze civil servant recruitment and not increase the budget of the body which runs the assembly
“We will not be abolishing the assembly, but we need to listen more” to those who wanted the Senedd scrapped, he said.
The party, he said, was “within a hair’s breadth of putting an end to Labour’s grip on power”.
In his speech, Mr Davies said that the 20th anniversary of devolution marked “20 years of failure” for many people.
He compared “elites” in Cardiff Bay to Brussels, saying many people felt remote from power.
But he said it was Labour, not devolution, that had failed and the Conservatives had consistently criticised the Welsh Government’s record on public services such as health and education.
The Labour Party, Mr Davies said, had wasted money on Cardiff Airport, a Pinewood film studio and the Circuit of Wales race track project.
He promised a Welsh Conservative government would upgrade the A55, build an M4 relief road and double investment in flood defences.
In a message to First Minister Mark Drakeford he added: “I’m telling you Mark, your time is up. I’m coming for you.”
Meanwhile Welsh Secretary Simon Hart told party members their party was “an unstoppable force” after the general election victory, claiming Paul Davies had a “realistic chance” of becoming first minister in 2021.
On Welsh Labour, Mr Hart said: “For a government to be in office every year for 22 years cannot be healthy”.
The conference comes after a second coronavirus case was confirmed in Wales and those attending have been urged to help curb the spread of the disease by using Conservatives-branded hand sanitiser and following the official advice.