When the Syrian civil war started, Iran was 600 miles from Israel.
Today the nearest Iranian soldier is just 20 miles from the Israel-Syria border on the Golan Heights.
Having the archenemy on the doorstep is Israel’s nightmare.
The Syrian regime is propped up by Iran and throughout the conflict the Iranians have sought to build up their presence inside Syria.
Their aim is to create a contiguous arc of influence stretching west from Iran, through Iraq and Syria to southern Lebanon, where their proxies, Hezbollah, prepare for the next war with Israel.
The Israelis say they won’t allow Iranian entrenchment in Syria to happen. Last year alone the Israelis dropped more than 200 bombs on Iranian targets in Syria. They have hit weapons depots, anti-aircraft installations and supply convoys.
The Israelis reckon they have managed to limit Iranian ‘entrenchment’to less than a third of what Tehran had hoped for by now.
But Iran shows no sign of pulling out. On the contrary, the Iranians will be hell bent on doing in Syria what they did in Lebanon. Look out for a Syrian equivalent of Hezbollah.
North west of the Golan Heights there’s now a huge wall running along part of the Israel-Lebanon border.
Feet from the barrier Israeli soldiers are being lowered down a 30-metre shaft to a tunnel dug by Hezbollah.
A combination of intelligence and technology has enabled the Israelis to find six tunnels and they’re pretty sure that’s all of them.
A major in the Israeli Defence Forces’ Underground Warfare Department (yes,really) said he and his colleagues were absolutely euphoric when the borehole they were drilling hit the first tunnel.
He said he had put a year and a half of work into the theory that cross-border tunnels were deep in the ground but that to actually find them was incredible.
He reckoned Hezbollah had spent more than four years cutting the tunnels, mainly though solid rock.
They had ventilation and electricity and were dug to enable Hezbollah fighters to emerge inside Israel to capture two border towns. The tunnels had not been completed when the Israelis found them.
The Major told me he wanted to put Hezbollah right back to square one and so the Israelis developed a special cement that they flushed through the entire length of the tunnels so they are blocked off completely.
Up until now the fight between Israel and Iran - and its proxies like Hezbollah – has been overshadowed by the Syrian civil war and the fight against so-called Islamic State in Syria.
But both those battles are almost over and the conflict between Israel and her enemies may now get more attention. It’s a worry for the world.