LONDON - Boris Johnson, the favourite to become Britain's next prime minister, said on Monday the impact of leaving the European Union without a deal would be "very, very small", and added that he had a very carefully costed programme of spending plans.

"There is as you know about 26 billion quids (pounds) worth of headroom. The money is there," Johnson told reporters when asked about his spending proposals.

"We also think there is room to make some sensible tax cuts as well and we will be doing that too."

The former foreign minister repeated his message that he did not think Britain would leave the European Union without agreement, but that there were many ways to mitigate the effect of a no-deal Brexit and its impact would be "very, very small".

Johnson also said there needed to be decent pay in a properly-funded public sector. ($1 = 0.7909 pounds)

(Reporting by Michael Holden; editing by Kate Holton) ((michael.holden@thomsonreuters.com; +44 207 542 3213; Reuters Messaging: michael.holden.thomsonreuters.com@reuters.net))