The evidence provided only contains general information about the UK and the US withdrawal from the Iran nuclear deal, but no independent sources specifically claim that the UK is facing the largest growth reduction from the Iran war compared to other G20 economies. This specific comparison is not supported by the gathered evidence.

One web search result mentions the OECD downwardly revising growth forecasts, but it does not specify a forecast of 0.7% for the UK. The other results mention general economic headwinds or different dates/figures, making the specific claim difficult to corroborate across multiple independent sources.

One web search result states that the OECD projects UK inflation will reach 4% this year, which is presented as an increase from a previous forecast of 2.5%. However, this specific prediction is not corroborated by a second independent source.

One web search result quotes the OECD downgrading forecasts for multiple economies due to the US-Israel war with Iran. While other sources mention general downgrades or conflicts, this specific linkage (OECD downgrading due to US-Israel war with Iran) is only present in one source.

One web search result mentions the OECD revising forecasts due to economic and political uncertainty, but it does not explicitly link the warning about prolonged high energy prices causing rate cut delays to the OECD's current warning in a way that is corroborated by other sources.

One web search result suggests inflation could hit 4% going into the autumn. While another source mentions inflation rising to 4%, the specific comparison (up from 2.5%) is only clearly stated in one context, preventing corroboration.

The evidence provided contains general information about the OECD and inflation forecasts but does not contain any specific, corroborating data points from multiple sources confirming that the OECD forecasts global inflation will drop to 2.6% in 2027, down from 2.1%.