Andy Burnham has warned against flirting with Brexit, telling a campaign event in Swansea that “this is not the time for equivocation”. He also said he will give no guarantees that he would sign up to trade deal TTIP.

The leadership contender pledged his commitment to the EU, saying that flirting with EU exit would put people’s jobs, communities and future prosperity at risk.

He argued that Labour must nail their colours “firmly to the mast” by being pro-European.

If elected Labour leader in September, Burnham said he would “instantly set about the task of securing our membership of the EU” by building a “grassroots movements in workplaces across the country”. He also noted that Labour will campaign for all 16 year-olds to be given a vote.

Burnham attacked the Conservatives for not speaking with one voice on the issue of Europe. The Tories “cannot be trusted to lead this important national debate. It would be a disaster if Labour was to follow suit. Under my Leadership, Labour will step up to the plate, fill this void and fight to secure the national interest,” he said.

However, Burnham criticised the Transatlantic Trade and Investment Partnership (TTIP), a trade agreement between the US and Europe, which could get rid of regulation that limits transnational corporations from making profit. Unions have in the past warned that TTIP will lead to lower wages and weaken labour rights.

He said he will give “no guarantees” to sign up to the proposed TTIP treaty. He criticised David Cameron for secretly seeking to “trade away the protections that Europe brings for British workers.”

“We will not win a referendum if people see Europe as a race-to-the-bottom, where a right-of-centre economic orthodoxy takes hold and the rules are written for the benefit of global corporations not ordinary people”, he said.

Burnham argued that there does need to be new rules to “protect the ‘going rate’ of the skilled workforce and prevent the under-cutting of wages.” He said more financial help needs to be given to communities most affected by migration.